This.
Faye is pretty much stuck at the age she was when her dad blew his head off. She's only just now beginning to develop into an actual grownup.
But I think the Faye analysis is the truth. Of course, that's because I also think (and have posted, somewhere) that Faye is 'stuck' emotionally, or at least was until she shagged the Himbo (Sven), and/or maybe a few days before, such as in the now legendary 'Underpants Talk' with Dora.
Did I mention I'd recently developed a dislike for Sven?
Actually, I'd say that this gives the Sven/Faye pairing *more* possibility, not less.
I think we'd agree that Sven is not as mature as someone his age should be, given that (according to Dora) Life has not done very much to challenge or throw obstacles in Sven's path heretofore. It is, after all, these obstacles that force us to both struggle and re-examine our beliefs, both of which add to our strength and maturity. So Sven is probably a little emotionally retarded and immature.
Faye, as Jeph state above, is also emotionally retarded, but for the completely opposite reason. Life gave her a HUGE obstacle, which she has not figured out how to fully overcome, and it has stuck her where she was as a college sophomore (about 19 y.o., give or take a year).
This means, despite their ages of ~27 and ~24, respectively, both of them are stuck in that place where you are just testing out your adulthood. Faye did it by leaving home and moving to New England to start over away from coddling and smothering at home. Sven is doing it by stopping the endless romantic gameplay and starting to invest his energies toward personal growth and responsibility. So, though they have travelled very different roads, both are at the same place in their lives, which frankly is a pretty scary place. That they might find comfort and support in one another is not unreasonable.
(Contrast this with Marten, who is not seeking any real change, and slides contentedly into comfortable, unambitious domesticity with his job, his band, and his love life. These qualities made him good for Faye trying to get herself back on her feet after the fire, and made him a perfect father-confessor for her trauma, but did little to press her buttons and make her react like Sven has done.)
Neither Faye nor Sven necessarily *need* each other, but I can see how they might be very *useful* for each other.
