I don't see why you all seem to think the thing with Sven is "her being stupid." We hear about his philandering past, but he's treated her nothing but graciously the entire time. Also, it makes absolute sense that she'd go for him and not Marten earlier -- When you're insecure about sex, you don't want to be with another person who is also insecure about sex. All you get out of that is one big insecure awkward implosion. They would have been *terrible* for each other. I like them both, they're both cute and it was fun to watch their (incredibly awkward) crush, but seriously guys, it would have been a huge mess. Sven, on the other hand, is comfortable with his sexuality and can show Faye what she doesn't have and so desperately needs in this arena -- confidence. On the other hand, *she* has something *he* needs, which is someone he actually respects and cares about to be with. Through each other, they can explore key aspects of their previous love lives that had been distinctly lacking, and I think that could be a really good thing for both of them.
Also, against all you Sven naysayers, I think he's amusing and actually a nice guy (*gasp!* Guys can be nice and have slept with a bunch of people? Crazy, I know) and personally I would've chosen him as well for the same reasons listed above.