I am cheating - what now?

I am in a five year long relationship with two children. My partner is an excellent parent and an amazing person, but he likely has a personality disorder. He has one negative emotion; anger. He is verbally abusive towards me when we disagree and he is quick to dismiss my thoughts and feelings ("That is ridiculous", "You are overly dramatic", "I'm not in the mood to listen to your whining right now") - at the same time as he gets angry because I do not share enough of myself with him. Any topic I attempt to address is taken as criticism. In addition, he has had problems with jealousy through-out our relationship, despite me being completely faithful until two weeks ago - to the point where I wouldn't even smile at or seek eye contact with other men beyond polite interaction. My hubby has, however, broken my trust on a couple of occasions. Not down-right cheating, but strayed away from the rules he himself listed when we first got together.

Now, this summary of problems is not to justify my actions. I am wrong to have an affair. It was not a moment of passion, but it is a deep on-going friendship with some physical/sexual interaction.

The problem I am faced with is that even if I cut my affair partner out of my life, I know for a fact my hubby would leave me immediately if he knew anything about it. Normally I would be keen on honesty irregardless and allow him to decide what he wants to do, but he has said that if I ever cheat, he "will hurt" me or "kill" me.

When I brought up the subject of ending the relationship, my hubby said he wants us to attempt couples' therapy. I have agreed to that, as I am rather out of other options. We parent together and I do truly love him, I do not wish to hurt him.

What would you do?