Let's assume you were a willing participant. I don't know your situation, how it developed, what kind of tricks they used to make you a consenting person, but, if you think deeply and objectively, you were.
Looking back on the bad relationships I had, with the wisdom, reflections and experience that age and life give us, I realize that I could have said no, taken a different path, lived a different life. Sure, they were bad, and I was bad with them and with others, but there was no chain holding me there, except the one I myself was willing to fasten around my ankle, perhaps because I was lonely, or scared, or immature. Or because sex was amazing, and they were a great cook, so sweet when they wanted to be.
Bad relationships should make us reflect on the faults of others, but especially on our own shortcomings. At least, that is I see them today, and my life got much better because of it.