Rachael, You've told him how you feel, now you will need to step back. Try not to allow him to engage you in any more discussions about the situation. He knows that what he did was very wrong and yes, he's trying to deflect the guilt and blame on to you. No one made him have an ea or pa w/the ow. He did that all by himself. He took the easy route out of trying to work on his issues. Had he been a stronger person w/a good moral compass, he would have tried to work things out w/you and a MC.
If he comes at you again for more discussion, just tell him you do not wish to discuss it any further. Your h knows what buttons to push to get you to react. You are the only one that is mature enough to control your actions.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.