Indeed. My ex was very adept at passing choice-making on to others so that no repercussions could come back on him. He was able to often say it was everyone else's fault and if pushed to take responsibility himself, he would get very caustic and nasty. His defense for cheating and leaving was "I have a right to be happy", but he was putting that happiness on the girl he left me for, he did not assert the needs and wants he had to be happy in our relationship. I think his mentality was "People either make you happy or they don't, it's beyond your own control".
In his eyes, it was my fault he was unhappy (I.E. it had nothing to do with the fact he did not talk about his needs or wants with me) and so it was easier for him to leave that way I think, he definitely did the demonizing of me after he left. The girl he left me for kicked out her then-boyfriend to take my ex in as well, I think they did the whole "I'm so glad I found someone who has been trapped like I have been!" thing. Tore me to pieces somethin' fierce at the time, but now I can laugh about it. It was the whole "YOU, NOR ANYONE ELSE, CAN STOP OUR LOVE!!!" and it was all very, very dramatic, lol.