my ex of 3 years left because..

Abbie
Well, my bf of 3 years left. His explanation? Nothing I did. He just doesn't stick in one place for to long and gets bored of the same people.
This is coming from the guy that has the same life and friends house and everything since he was like 7. Also a 4 year relationship before me. I can't help to think there was something else. 
He says I did nothing and I gave him the best 3 years of his life. But then why leave?
He always said forever and love and talked marriage for awhile then just abruptly stopped. 
I know he wasn't right for me because he DID treat me kind of bad. But I delt with it because I loved him.
And the worse part? The friends I DID tell that we were done, don't even care that I'm in a hard place. My life doesn't fall apart without him And I'm always the one that has to help everyone else but it would be nice to be asked if I'm okay... because I'm not.