According to the catholic teaching, in the marriage, the marital act is a moral right for each spouse and a moral obligation for each spouse: therefore, the practice of marital act is the principle and the exception is not to practice the marital act. In catholic moral, there are only two systems for abstinence of marital act:
A. The bilateral agreement between spouses, the mutual and reciprocal will of each spouse not to practice conjugal sex:
- During a temporary time for spiritual and religious reasons, in knowing that at each time (at each second) the agreement can be stopped by the will of only one or by both of them. The break of this temporary time without sex is not immoral and is not a bad event for the couple, it is not sinful.
- During the time where there is a presumption of fertility of wife for serious reason(s) (grave, objective, real and fair) in order to avoid a baby (to delay and to postpone the arrival of another child) or for the spacing the pregnancies: the N.F.P with the different natural methods.
B. The unilateral will from one of member of couple:
- If and only if there is a serious motive, (thus the refusal of the request of marital act from wife or from husband is morally okay);
- For the wife during pregnancy if and only if there are realistic medical issues or if the wife is tired by the pregnancy. Per se, the pregnancy is not a reasonable reason, it is not enough, it is irrelevant.
- For wife, between 2 weeks and 6 weeks after childbirth.
- For wife during the menstruations if and only if she is tired because per se, menstruations are not reasonable causes, it is not enough, it is irrelevant.
- If there is adultery, but after the forgiveness, the marital sex is the rule, the refusal is not morally licit.
- If the request of marital act is too often in the short time (the moderation): but no number and no quantity, per se, can be given like example.
- If one of member is drunk or has lost temporary the reason.
Each time, **the reasons have to be reasonable, real, objective, fair and serious. Why a reason, **because the marital act is the rule of the state of marriage. **Of course, the unilateral refusal of marital act can be immoral, sinful (venial or mortal) if there is no reasonable, real, objective, fair and serious reason for justifying the refusal. **The systematic rejection or refusal of request of marital act is wrong, is dangerous, and is probably sinful: it is against the state of marriage. Marriage means the fact of making one flesh (marital act between spouses). **A rejection without a very good reason is wrong and immoral. **
Of course, t**he marital rape is a concept that is recognized by the catholic moral and that this type of behavior is very wrong , immoral and awful (it is going against the conjugal love): very sinful, it is a crime. **Of course
none has the moral right to force the other for having conjugal sex. But, each one has to make sacrifices and respects the vows of marriage.