Lack of awareness and knowledge about female pleasure and the sexual organs.
Not even mostly they're own fault, really. The knowledge is out there but nothing in an average young man's consuming of knowledge makes them even aware of the issue unless they make the mistake with a woman in the first place.
Better sexual education'd help. Or slightly more realistic porn.
I don't think so, because that tag means she wouldn't be gay without the money... Also, I don't think prostitution is the case because technically she isn's a prostitute, she didn't believe she would get paid.