For the past 40 years,the old,languishing FREE LOVE MOVEMENT took off,so sex can't really be the reason men marry now....The "what one is supposed to do"? doesn't work either.Time was,when both were a valid supposition;not now.
Oh yes, I don't agree with this part. I think that men still marry for sex, despite the whole free love thing of the sixties (which was actually tied to technology, but that's another discussion).
Sex is part of it,but since people openly live together now and have sexual flings,both of which was almost unheard of 40 years ago,on this scale,I think that you are over emphasizing that part of it in today's reasoning.But,not being a man,I may be deemphasizing it a bit more than needs be.We need a happy medium and a ref here. LOL