Well, there are different things that come into play.
1. Alot of Men don't deserve to get married with how their attitudes are.
2. It cost alot of $$$ and we are in a recession.
3. A woman can just dump her man and go with some guy who is rich, or who has a huge dick.
4. With modern relationship ethics, it's rare to find something that would work.
Would YOU want to marry a woman who would be likely to leave you for another man because he is better in a way and then get fucked in divorce court? I wouldn't.
Or would YOU want a man who would cheat on you and/or beat you and doesn't give the respect and loyalty you deserve? I wouldn't.
It's just easy to go get a fuck buddy, get off, and be happy for a few days.