1.) When Blaine was born, his mother died, his father blames him for her death. His father has always hated him, Cooper was always famous so he never spent time with Blaine. The people at his old school hated Blaine even before he came out and everyday they would beat him up, and when he got home his father would yell at him telling him to man up. Blaine had no friends, even before he came out, and at the SH dance, he went alone (not wanting Kurt to feel pity on him so he lied) couldn't take the fact that people were happy when he wasn't left after a few minutes, gotten beaten up so bad, he was put in the hospital for about a month and week, the one week being in a coma. His father transfers him to Dalton, then disowns him, Dalton hears about Blaine's story and then makes the 0 tolerance for Bulling policy. After about a year, he meets Kurt, then finally thinks he found someone who actually could care about him, they start dating but then feels like Kurt loves NY more than him. -in this theory, Blaine is a nerd but when he transfers to Dalton, he changes his looks and interests and makes a vow to make sure no one ever gets hurt like he did-
2.) When Blaine was 6 he was kidnapped
3.) Blaine hates having people think he is weak, he acts strong, but he really just wants to cry, he acts strong because he doesn't want pity parties.
I will right more, but right now i am just too lazy