I think that is a perfectly understandable boundary, Puddle. I had a similar situation when my H, when he was still living here, would take his phone to his bedroom each night, when normally he just left the phone on the counter downstairs at night. I knew he was TMing the OW when he went to bed (I found out about the A by finding the TMs one night) and it made me ill to know he was in the next room doing that. It certainly didn't help my ability to sleep!
When my H moved out, it was a huge relief to know that crap wasn't going on under my roof anymore. I didn't have to walk past his closed bedroom door and wonder what was going on in there.
I guess what you have to figure out is how you are going to enforce this boundary. I'll have to go back and look because I am not sure I know where you and H are on the subject of separating or not. Are you willing to ask him to leave if he refuses to stay off the phone w/ OW in your house?
I just want to say, too, that I am sorry that he is doing that in your home. I remember the sick feeling I carried around when it was going on in my house, and it is not fun at all.
