"He's my character," she asserted. "I have the right to know what I know about him and say what I say about him."
http://www.theglobeandmail.com/servlet/story/LAC.20071024.ROWLING24/TPStory/Entertainment
Dumbledore and Grindelwald
Because Dumbledore's parents were absent (his father being in Azkaban and mother deceased), Albus became the head of the family and it became his duty to put food on the table (they were not left with much gold). He was forced to remain in his house with his sister Ariana while Aberforth completed his education. Soon later, a young Gellert Grindelwald arrived in Godric's Hollow to live with his great-aunt, Bathilda Bagshot, author of A History of Magic. The young Dumbledore fell in love with Grindelwald, and together they dreamed of ruling the world "for the greater good" by uniting the legendary Deathly Hallows.
Both wizards had the idea that the Wizarding world should take its rightful place on top of the Muggles, and both believed that wizards should rule over them and put them in their rightful place amongst the entire world. Even if they were forced to destroy a few along the way, it would be "For the greater good" and that the sufferings and losses would be rewarded a hundredfold in the end. However, a discussion between Albus, Aberforth and Grindelwald led to a duel that resulted in Ariana's death. For the rest of his life, Dumbledore felt guilty, never certain whether it was his own curse or another that had actually killed his sister.
Grindelwald stormed back to Bagshot's home and departed to begin his own rule. Meanwhile, in Ariana's funeral, Aberforth became enraged during the service and punched Albus in the nose, breaking it, giving its known crooked appearance. Albus later felt great remorse for his mistakes during adolescence. As a result of them, he felt that he was not to be trusted with power and, because of this, never took the position of Minister of Magic, despite having been offered several times. Dumbledore retured to Hogwarts as professor of Transfiguration, and most likely later became Deputy Headmaster of Hogwarts as he also served in recruiting students for the school.
Dumbledore finally defeated the now-Dark wizard Grindelwald, who had come to possess the Elder Wand. After Grindelwald's defeat, Dumbledore became true master of the Elder Wand, which has been his wand until his death, regarding it as the least of the three Hallows, and the only one he was fit to wield.
While speaking at Carnegie Hall on October 19, 2007, J.K. Rowling was asked by a young fan whether Dumbledore finds "true love". Rowling said "Dumbledore is gay" and that he had fallen in love with Grindelwald, who did not return his affections. That love, she said, was Dumbledore's "great tragedy."
http://en.wikipedia.org/wiki/Dumbledore
Again. Her comments were AFTER the book.
As for you quoting Wikipedia? Please, you’re embarrassing yourself.
Oh please. Wikipedia? Since any fool can write anything they want there, on any subject, I’ll go with what I already KNOW, not what some fevered imagination can concoct.