There was a comment somewhere that said it good in few words. That he doesn't have to shag, he doesn't have to kiss her, he just has to let her know she's great.

Cos I'm hard-pressed to even read them ending up as friends. He was so cold when he left, like he wasn't bothered either way. Maybe it's a reaction to previous excesses but I don't think I could watch another year of the Doctor being so heartless.