Marital infidelity is a breach of the marital relationship by either of the husband or the wife. In other countries, adultery is the only form of marital infidelity. It is defined as the voluntary sexual intercourse between a married person and a person who is not his or her spouse. In the Philippines, there are two forms of marital infidelity. That which is committed by the wife is adultery and that which is committed by the husband is concubinage.
In the past, this has been an accepted norm in the form of polygamous marriage since the man was allowed to have more than one wife. As time went by, the Filipino culture had changed and polygamy became unacceptable in the society but marital infidelity has not been avoided. The Revised Penal Code (RPC) considers adultery and concubinage as crimes and provides for the punishment of both to protect the sanctity of marriage, and more importantly, the family as the foundation of the nation
However, there seems to be an imbalance in the treatment of men and women found guilty of the crime. While both aim to punish the marital infidelity of the spouses, there is higher burden put on wives than on husbands. The penalty imposed is higher on married women who commit infidelity as compared to married men. The penalty for women ranges from two years, four months and one day to a maximum of six years, while the penalty for men ranges from only six months and one day to a maximum of four years and two months.
The disparity of treatment seems to be gender-biased and discriminatory. It seems to accept the infidelity of men as normal, but more stringent on women who are expected to be faithful to their husbands.
Section 12 of RA 9710 or the Magna Carta of Women (MCW) provides for the amendment or repeal of laws that are discriminatory to women. The 1987 Constitution, Article II, Section 14 provides that the State recognizes the role of women in nation-building, and shall ensure the fundamental equality before the law of women and men.
Thus, Article 333 and 334 of the RPC which provides for the punishment of adultery and concubinage should be revised in order to address the issue of inequality produced by the current provision.
The National Commission for Women defines marital infidelity as a violation or breach of good faith and confidence by one or both spouses to the matrimonial vows. It is also a major spousal pressure that eventually causes the breakdown of marriage as a foundation of the family.
In Europe, adultery is no longer a crime. Among the Western European countries to repeal their laws were Italy, Malta, Luxemborg, France, Spain, Portugal, Greece, Belgium, Switzerland and Austria.
In the Western countries, the United States is one of the few industrialized countries to have laws criminalizing adultery. As of 2017, adultery remains a criminal offense in 21 states, but prosecutions are rare.
Among non-Muslim countries in Asia, it is only Taiwan and Philippines which define marital infidelity as a crime. In India, Section 497 of the Indian Penal Code states that adultery may be committed only by a man who engages in sex with the wife of another man who did not consent to the act. At first it can be viewed as discriminatory against men, but substantially it is degrading to women as it treats them as their husband’s property. A husband can consent to his wife’s adultery and she will not incur any criminal liability. In South Korea, the nation’s top court abolished the law that made adultery punishable with a prison term. In China, marital infidelity is more of a moral than a legal crime as they do not have any legal provision to punish such act. In Japan, adultery and infidelity are time-honored Japanese traditions for the nation’s men.
In the Philippines, before the arrival of the Spaniards, the native Filipinos already had their own relationship practices. One of those is the usual practice of polygamy. Early Filipino tribal man had five or more wives, a marital ethnic norm at that time. When the Spaniards arrived and introduced Catholicism to the natives, the missionaries promoted Christian ideas of the wife’s fidelity to her husband, premarital virginity, and the notion of a woman’s role as a nurturing mother and the reverence of the Virgin Mary.  Perhaps it was then that monogamy has become more acceptable in the society rather than the traditional practice of polygamy, except for those who have not converted to Catholicism such as the Muslim community and other indigenous tribes. But even those who were converted, extra-marital affairs were not prevented. This was mostly hidden from the society to avoid judgment. As time went by, aside from being an unacceptable social and moral norm in most Filipinos, having extra-marital affairs or what is commonly known as adultery and concubinage has been included in the crimes punishable by law.
At present, adultery and concubinage is considered as crimes against chastity. In the Revised Penal Code, both crimes are punished by prision correccional in its minimum and maximum periods. But charging a husband for an extra-marital affair in court is harder to prove since the wife has to prove any or all of the following: a.) He has kept a mistress in the conjugal dwelling, b.) He shall have sexual intercourse with a woman who is not his wife under scandalous circumstances, and/or c.) He shall cohabit with her in any other place. On the other hand, for a wife to be charged with adultery, proof of sexual intercourse between a wife and another man who knew of her civil status is all a husband needs to charge her with adultery. The penalty for the husband’s concubine is destierro while for the man in adultery is the same as that of the guilty wife. 
The ways of proving the crimes of adultery and concubinage seems to be unfair on the part of women because it is usually hard to prove that the husband had kept a mistress in the conjugal dwelling or cohabited in any other place. While the proof to convict a wife for adultery which is the sexual intercourse to a man who had knowledge that she is married is easier to prove compared to the case of concubinage. Moreover, the penalty for a concubine is lighter than the penalty of the man in an adulterous affair.
In the case of Ocampo vs People of the Philippines, the court held that Luis Ocampo was found guilty of the crime of concubinage and sentenced to an indeterminate penalty from six months of arresto mayor to two years and eleven months and ten days of prision correccional, while his concubine Igmedia Refe was punished with destierro. Destierro is the banishment or only a prohibition from residing within the radius of 25 kilometers from the actual residence of the accused for a special length of time. Destierro is not equivalent to imprisonment.
In the case of Virgilio Maquilan vs Dita Maquilan, the wife Dita and her paramour were both convicted with the crime of adultery and sentenced to suffer an imprisonment ranging from one year to eight months, minimum of prision correccional as minimum penalty, to three years and six months and twenty one days, medium of prision correccional as maximum penalty.
In Article 2, Section 14 of the1987 Constitution, the State recognizes the role of women in nation-building and ensures the equality before the law of women and men. Article 2 (g) of the Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) requires the State to modify or abolish existing laws, regulations, customs and practices that constitute discrimination against women. Article 16 also calls on the State Parties to take all appropriate measures to eliminate discrimination against women and ensure equality of men and women in all matters relating to marriage and family relations.
There is a need to amend and update Article 333 and 334 regarding the evidentiary requirement of the crimes against chastity and the penalty for the concubine and the man charged with adultery. Equality before the law should be considered. The proof for a husband who committed concubinage should also be the same as the proof of adultery. The need for the proof that a husband kept the mistress in the conjugal dwelling or cohabit in any other place should be removed because as observed nowadays, men are more likely involved in extra-marital affairs than women. One reason to be considered for this act of men is that concubinage is harder to prove than adultery. So the penalty for adultery and concubinage should be increased in order to discourage the commission of these crimes and protect the marriage because it is the foundation of the family, and the family is the foundation of the nation.
A counter-argument regarding the discriminatory effect of Article 333 and 334 of the RPC contends that penalty for women in adultery should be higher because an illicit affair between a wife and her paramour could result in an illegitimate child who would become the unknowing husband’s spurious heir.
This argument is not enough to be the reason why the Congress had not yet approved the bill to amend the Article 333 and 334. It is more likely because there are more men in the Congress than women. For men, it has been normal and blatant that most of them commit infidelity to boost their morale. Unfaithful husbands assess that infidelity is okay as long as they can afford it and/or provide the material needs of the legitimate family. Other reasons of husbands for their infidelity are lack of sexual intimacy with the wife, inability to communicate of both spouses in healthy ways, being disillusioned with marriage and poor relationship with Christ.  For women, some of the reasons why they commit infidelity are (1) when she feels underappreciated, neglected or ignored, (2) she craves intimacy, (3) bored or lonely, (4) never feels fully loved and appreciated, (5) she has intimacy disorder. 
Various studies show that men are more likely to commit marital infidelity than women. From the website of East Asian Pastoral Institute, Ted Gonzales, S.J. wrote that the husband’s infidelity is a major concern in Filipino marriages. Carandang (1987) noted that the wives rank infidelity as the number one family stressor. Lacar (1993) reported that male infidelity is the most frequent reason for marital separation. Vancio (1980, 1977) cites male infidelity as a major issue for marital break-ups in Metro Manila. In the McCann Metro Manila Study (1995), half of the 485 male respondents reported having had extramarital affairs. Relucio (1995) in her in-depth interview with seven separated women noted that infidelity was found to be a common problem. 
Aside from the counter-argument regarding the discriminatory effect of the punishment of Article 333 and 334, there is also an argument to decriminalize adultery and concubinage. According to the United Nations Working Group on decriminalization against women in law and in practice, “maintaining adultery as a criminal offense, even when it applies to both women and men means in practice that women mainly will continue to face extreme vulnerabilities and violation of their human rights to dignity, privacy and equality”. By decriminalizing adultery, the State eliminates such risk and vulnerabilities to further discrimination. The criminalization of infidelity is an invitation of too much government interference into the personal lives of people including on matters that should be dealt with privately. 
The Family Code of the Philippines states that marriage is a special contract of permanent union between a man and a woman entered into in accordance with law for the establishment of conjugal and family life. It is the foundation of the family and an inviolable social institution whose nature, consequences, and incidents are governed by law and not subject to stipulation, except that marriage settlements may fix the property relations during the marriage within the limits provided by this Code.  To rebut the argument regarding decriminalization of marital infidelity, striking this off in the list of crimes would rather destroy the sanctity of marriage because this will be done easily by any or even both of the spouses. There is a need for the State to interfere in the marriage because the Constitution considers marriage as an inviolable social institution and is the foundation of family life which shall be protected by the State. The State can find no stronger anchor than on good, solid and happy families. The break-up of families weakens our social and moral fabric. Hence, the preservation of the family is not just the concern of the family members, but of the State as well.
Decriminalization can be a public health issue too. Without a law criminalizing marital infidelity, a married spouse may be involved with someone already infected with Sexually Transmitted Diseases (STD). Since most married couples do not routinely use contraceptives, the innocent spouse may be infected with STD.
In order to settle conflicting issues regarding the decriminalization of marital infidelity, the solution to be resorted is the one favorable to the State and most importantly to the family. The treatment of marital infidelity as a crime against chastity to deter spouses in committing it should remain. But amendments to the evidentiary requirements and punishment should be done in order to balance the discriminatory provisions of the law.
Therefore, the punishment for adultery and concubinage provided in the Revised Penal Code is discriminatory and gender-biased. Adultery and concubinage comprises marital infidelity in the Philippines. Beforehand, it was a common practice of the ancestors as a status symbol. But at present it is considered as a crime against chastity.
In other countries with different cultures, marital infidelity is treated differently. For some, it is an acceptable norm of the society which had been passed by their ancestors. While for others, it is considered as a crime. Different punishments are imposed by different countries who consider it as a crime.
The punishment in the Philippines is biased and discriminatory because there is a higher burden put on wives than on husbands. The disparity of treatment of the law is seen in the evidentiary requirement for adultery and concubinage and there is a huge difference in the sentence for those who are convicted.
There is a need to revise the punishment and the evidentiary requirements to effect equality between men and women as stated in the Constitution. Several bills have already been submitted but are still pending in the Congress. It has been announced that the President had already approved the new Penal Code which will be an update of the provisions of the current RPC. But it has not yet been issued to the public, so it is hoped that the punishment for adultery and concubinage will be included in the amended provisions.
1 Section 497, Indian Penal Code
Brewer, Carolyn, Holy Confrontation: Religion, Gender and Sexuality in the Philippines 1521-1685, 2001 edition, Manila.
3 The Revised Penal Code of the Philippines, 2016 edition. RBSI, Manila
8 Rabuya, Elmer T., Persons and Family Relations, 2017 edition, RBSI, Manila.