Mostly, it's been mutual and relatively amicable.
The worst was the first. He told me he wanted to be with me and spend the rest of his life with me, just not right now. But he didn't want to break up with me. So I said, okay, how about we take some time off. He said no no, he wanted to stay with me, though he felt trapped. In other words: he manipulated me into breaking up with him.
I kept sleeping with him for an embarrassingly long time after that, with him saying he'd want to get back together "officially" soon. He even set a date for when we'd be back together. Then that date passed with him saying he wasn't really ready yet... but I was still totally in love with him. Oh, and he told me that he was thankful I'd broken up with him, but that he would NEVER have broken up with me. Finally, we came to a point where my body actually refused to have sex with him. It's smarter than me a lot of the time.
It took me years to be ready to date again after that, it really messed me up.