Mmmm ... it's true that a marriage takes two people and one isn't to blame for everything and the other guiltless ... BUT

You aren't to blame for him cheating. That is a huge failure on his part. That, to me, is the most dishonorable thing a man can do.

Everyone, including yourself, deserves to be treated with respect and dignity. You have a lot to work through. Accept responsibility for your mistakes, but don't accept responsibility for his.