--H cannot feel good around you when he is lying about PW. He will project and make it a problem with you, but the real problem is his own guilt.
-- "H, I want you to know that I don't want to be a default wife anymore than you want to give up on yourself. I am open to trying this R and seeing how it works for both of us. I think I get that you open to the same. If so, then we both need to be very clear on the fact that we are working on the M together, but if it doesn't work out and one of us leaves, that is really OK. I want an M where we are both freely choosing to be in it together, and that can only be the case if we both feel free to make other choices. We just need to be honest about what is going on."
-- Too bad if you get hurt if H leaves again. It is your choice to take the emotional risk of trying to reconcile. You accept the emotional consequences. Of course he knows you will be hurt if he leaves again, duh. But you really need to take ownership of the risk and consequences. By no means hold it over his head. Do the opposite. Take ownership and tell him you are a big girl and can handle the consequences of any emotional risks you choose to take. If you cannot say that and mean it, then I suggest you separate until you can.