If you believe that romantic love is the only thing that matters, perhaps. If you believe that having a 'one true love' means that you never care about anyone else every again, perhaps.

I don't believe either of those things. The Doctor can have been 'in love' with Rose and that doesn't change his adoration of his granddaughter or his affection for Sarah Jane, Liz, Jo, Ace, etc.

The Doctor is capable of caring about many people, in many ways. And just because I believe that Rose is the only character that he was 'in love' with, does not mean that I believe she is the only character that he loved.