Well, who knew Kelsey was a candidate for a "No Fat Chicks" t-shirt? I woulda never guessed.
I liked the insights into why Kelsey had cultivated such an easy-going, willing to please manner, and I think that it provides a good explanation for why he might stay with someone as petulant and annoying as Teya. (Well, that and the possibility of being turned into Slayer kibble.)
His sudden concern with her weight seemed a little abrupt, but that could be because there were so many other things to dislike in Teya that I'd think a little hippiness would be a minor issue. Of course, if your goal is to portray Kelsey as essentially shallow and weak-willed underneath his eager-to-please exterior, I'd say it worked.
One nit: I'm guessing that "readheads" in the first sentence should be "redheads". There was a near-duplicate paragraph toward the end too, but it looks like you corrected that.