Because it's script, and the odds are in favor of it happening, because she could either:
1) Try to be PHONY nice, as someone suggested above, to show that she has all the sexual power in the relationship; or
2) Respond genuinely, and physiologically, to what is very manly, leading behavior. Remember, the opposite of love is not "hate" -- it's "apathy."
I could be wrong, of course. NOP predicted it in my sitch, at a time of MAXIMUM tension between my wife and I (ok, let's call it what it really was -- SHE HATED MY LIVING GUTS), and I thought he was nuts. He said "within the week."
