I still like this part too: "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 are 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."
It might actually be two conversations, that an the PW boundary convo.
Anyway, I really wrote to reiterate that I don't think you should determine what your future boundaries will be. This is for a lot of reasons. But two quick ones. First, you really don't know. I don't if someone asked you 2 years ago if you would tolerate the current sitch, you would have said yes. Second, why not give him a chance to come to the place you would like him to be on his own, given that you are willing to tolerate contact right now?