Bwahahah - that's priceless! He's not wrong though. The more I see of her on this rewatch, the more annoyed I get. I didn't write anything up about rewatching New Earth last week, but that bit at the start where she's all gushy - "travelling with you, I love it" and he's just as bad - really makes me cringe. I'm sorta thinking now that Rose was a kind of infatuation for him; Nine comes out of the Time War (I'm assuming it was Nine rather than Eight) all battle-weary and guilt-laden, and he meets this refreshingly unaffected kid who trusts him and who is able, in some circumstances, to challenge him in a way he hasn't been for a while, and so he becomes rather taken with her. I liked Rose with Nine. But when Ten came along, it all changed and became more lovey-dovey - which I suspect had a lot to do with the fact that they now had a very attractive man playing the character, and many of the subtleties that had made Rose's relationship with Nine one that I wanted to see just disappeared.

I want to say something about River as well, but I'll do that in response to your other comment :-)