Who is dumbledore love interest?

According to J.K. Rowling, Dumbledore was "infatuated with rival Gellert Grindelwald". It is not made clear whether the two ever went as far as becomming lovers, though. Basing my assumptions on interviews with J.K. Rowling and information contained within the seven Harry Potter books, I do not believe Dumbledore had any love interests after Grindelwald as that infatuation ended in catastrophe. Although, if you are interested in reading about Dumbledore's "gay lover", I'm sure you can find a lot of fanfiction out there, some streching canon far beyond it's limits. I recommend AdultFanFiction.net. Good luck.