After being officially credited by all my friends as, "the worst boyfriend ever" I have to agree with the OP, so many whipped men out there.
I think the fundamental error most men make is believing just because they found a woman who'd put up with them and occasionally let them have sex with them that in someway that makes that woman special.
When in reality if said woman just got up and left one day you would find one just as good or better without much problem. The fact is there are over 3 billion women in the world. That strikes me as a very large pool to pick from.
Also some people are just lazy and stupid and use the excuse that the girlfriend/wife doesn't want them to do something to get out of doing it.