Because the only other reason that I can think of would be that he's sad that Cate, a chick on the other side of the planet, is now taken, and, come on, that's just silly. People beyond ll-years-old don't think that way.
Yeah, I read a review that said they think House is in love with her. Um, no. Not to deny the extraordinary connection they had, but come on. It doesn't work that way.

I have a hard time believing such a confrontation would result in canon House/Wilson. I worry that all we'll get is a Sean/Christian type situation, without all the sexy gags.
I'm really hoping it doesn't turn out like Nip/Tuck (I think it worked for those characters, but not these), especially since there are at least two writers that support H/W. I'm expecting even more ambiguity that they're experts at, although I have no idea how they'll pull it off. (Now what I want is another thing...)