S&D, I completely understand where you are coming from. After first BD, my H wanted us to have a trial separation, living under the same roof (he couldn't afford to live on his own either). I agreed only because I thought that we were going to eventually come back together and work things out. He wanted to see other people and I set a boundary that as long as we lived in the same house, I didn't want to see other people. He agreed. When I found out about OW for the second time (they broke up and secretly got back together), I restated my boundary and asked him to leave. He said he couldn't afford it, I said stay at a friend's house, I didn't care (OW lived 5 hour away). He left and stayed at a friends and hasn't moved back - it's been over 3 years.
Have you served your H with legal separation papers?