If it gets to that point, then she needs to get a divorce. I mean these two people have probably had sex who knows how many times, and suddenly the cops need to get called in because he wouldn't stop when she told him she has a headache? Don't drag law enforcement into a situation that should be a private matter between a husband and wife.
How often you've had sex doesn't matter. Just like: how often you walk into the gas station to buy a pack of cigarettes does not make it okay to walk in one time and steal a pack. 100 rights don't permit 1 wrong.
Where *do* you draw the line?
1) There's: Not being in the mood but going 'okay, I guess' and being willing-reluctant.
2) There's: When you're pinned down and forced into it spite what you say or what you want?
3) There are other mean of coercion and there's guilt.
4) It could become violent (if you don't consider the act of forcing yourself into someone to be violent). Smacking - punching - or hitting with objects - or threatening to hurt the children or pets if she doesn't give in, etc.
You know - when does it become acceptable for someone to seek outside help? What are the guidelines, here, since you think everything private and neither person has the right to seek out help.
What is it about the act of marriage that removes you from the basic concept of seeking outside help? Divorce is a final end to an established lifestyle and it has wide reaching effects. In order to divorce you have to be able to support yourself.
On the other hand: law enforcement is a quick end or response to an immediate situation. Further: going to LEO can substantiate things and help you put that distance needed between you and the person your with in order to get separation and a divorce. Example: LEO's can take you to a safe house where your partner will not be able to contact you and through that you can start a new life.
If a married person is willing to rape their partner then "please leave me alone, we're getting a divorce" probably isn't going to end the situation. I don't know where your head is - but your view is not grounded in reality.
Domestic violence isn't a private issue. - That belief is exactly how so many people are trapped in a situation where it keeps happening, and it keeps happening, and it happens again and again - because they believe it's a private matter and they shouldn't tell others or seek REAL help.