1 Cor 7
2 Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband.
3 Let the husband render unto the wife due benevolence: and likewise also the wife unto the husband.
4 The wife hath not power of her own body, but the husband: and likewise also the husband hath not power of his own body, but the wife.
5 Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency.
6 But I speak this by permission, and not of commandment.
I come away from reading Paul's statement above with the following impression...
1) Paul considers marriage as a contract that each has access to (authority over) the other's body. Don't get married if you don't accept this.
2) To deny the other access (sex) is to default on the marriage contract or to defraud the other.
3) Thus Paul says it is WRONG to deny one's partner sex.
4) Other scriptures clearly shows that rape is VERY WRONG and would be EQUALLY WRONG in marriage.
5) Paul states that if partners are going to deny each other sex, it should be by mutual discussion and consent.
6) This denying sex should only be for extreme reasons, such as fasting.
7) Immediately after the fast, normal conjugal activity should recommence.
8) To deny another sex opens the marriage partners to Satan's temptations.
9) One of those Satanic temptations may be to rape the wife.
10) Other ways may be for the frustrated partner to find relief elsewhere.
This is now my tuppence worth ...
1) If one partner denies the other sex, this is WRONG. But rape is obviously not the solution. Two wrongs never make a right.
2) The wronged or denied partner can initiate a separation for a while. This is a Biblical option, and is used to try to bring the other person to their senses.
3) If this fails to produce results, take it to a minister who should try to encourage compliance.
4) If this does not work, learn to live without sex. Failing this there is divorce which always is the last resort for "the hardness of your heart" or the unconverted "Christian".
5) I believe every person has a right to not feel in the mood once in a while, and that is just tough. Live with it.