The Oscar-winning actor, who was married to Jolie from 2000 to 2003, says his wife's increasing fame made their relationship more difficult, the Daily Mail reported.
"Angie, I felt, was definitely too good for me and at some point, if you believe somebody's too good for you, you're going to mess it up. I always thought I was sort of Quasimodo or the Phantom Of The Opera hiding in the catacombs. And when I was with her I think that really reached its heights," the 56-year-old actor told US TV show Nightline.
"I blew it. When you're in a relationship, any two celebrities or whatever that puts on a lot of pressure. When Angie and I got married, during that time, I was more famous than she was to start with and then she becomes this big thing, it's hard in these relationships. People have actually said that I didn't deserve to be with her."
Jolie has moved on in her life and raises six children with her long-time partner Brad Pitt, whom she got engaged to recently.
She, however, continues to remain on good terms with her ex and has even written the foreword for his new book 'The Billy Bob Tapes: A Cave Full of Ghosts'.
Thornton too is proud of his ex-wife's achievements in life and feels Pitt is the right man for her.
"We're great friends and always will be. I'm proud of the way she's handled having a family. She's great for Brad, Brad's great for her. I support them 100 per cent. Angie is a little girl and a woman and a teenager and a ghost all wrapped up in one."
