I watched an interview of the girl who plays River Song, and she describes the Doctor as "just at age 900 growing into his sexuality," meaning that the Doctor is just now becoming a teenage boy. He was very in love with Rose, as was she with him, however both of them had a hard time admitting their feelings. Think of it this way: When the Doctor regenerates, he becomes a new person, both physically and mentally. His memories are still the same, but the way he views a person might not. For example Rose and 9 were just friends, but Rose and 10 fell in love, however once 11 came along Rose was pretty much forgotten by the Doctor even though 10 spent so much time "mourning" (for lack of a better word) her. When 10 kissed all those people it wasn't because of his feelings for them, it was either part of a plan, or a goodbye, or something like that. 11's love was River Song. This explains why the Doctor has had multiple "true loves". And by the way, it was made very clear by 10 that he was not in love with Martha and only considered her to be a friend.

the whole Rose /10 thing was horrible. why would a person who is at least 900 years old fall in love with a human teenager(this would be sort of like a 90 year old man having a 5 year old girlfriend). This was only due to Russel T. Davies trying to turn the show into a teen soap opera, which it is not The Doctor is not ment to be falling in love with his companions

Not even close. Romana was his true love, probably followed closely by River Song.

when the show started in 1963, the doctors granddaughter travelled with him, so if he had a granddaughter.......

river song / melody pond must have been his love too.

he was also a lover (husband?) of queen elizabeth 1.

Wow the 10th doctor has been off the show for a while now but im just starting it lol. Anyways, Rose and the 10th Doctor both love each other but never kissed. In season 3 he kissed Martha and that nurse from when he turned human for like 2 episodes. In season four he kissed Astrid and im only at the first episode of season four but i wouldnt be surprised if he kissed someone else. However, he and Rose never kiss. Is it because he is so truly in love with her he just couldnt bring himself to and then the other girls he just really liked? Sorry if its kind of hard to understand the way i set it up.