I had a terrible childhood (parental abuse, bullied my entire schoolyears) and I think I have autism, which explains why everyone always thinks I'm so weird.
But what put me over the edge is my last breakup. My last two relationships almost got me, but now the last third one was just too much to bear. It made me realize I will just keep repeating the same pattern of destroying whatever it is I love.
I will never forget the look in her eyes when she told me she slept with another guy (after we broke up). It destroyed my soul.