I know exactly what you mean. In your shoes, I would definitely cut out the intimacy.
My problem is, H is so far away and I can't ask about OW, so I have no idea if she is in the picture or not. If she isn't and I cut out ML, I hurt my sitch. If she is still around, and I don't stop the intimacy, I am letting him cake eat. I feel the same as you - he can't have us both, but how do I know?
In your case, although it is hard (believe me, I know) I think you are making the right decision. You've laid down a boundary. That's great. Just be prepared for his reaction. If you can let his anger or his retaliation roll off you (or at least let him think you're not affected), he may eventually stop trying to "hurt you back."
Me: 59 and holding H: :53 Me: 1 S, 1 D, both grown M: 19 T: 23 BD: 9-23-2013