Every dictionary definition: Nope. Of all the dictionaries (legal and regular) ever written, only a very small percentage written in the very recent past in a few very specific paces would define anything that occurs within a marriage using the legal term "rape."

As for a marital contract: I've never signed one and I've been married for 32 years. I doubt you did either. We did take vows though, and those vows include ongoing consent to fulfill our marital duties.

I (somewhat) agree with your last statement, although I'm not a fan of divorce except in the most extreme cases (and rarely even then if there's any other way), but abandonment of the marriage (which is what enforcing a dead bedroom is), is pretty serious.