Ro, I went through some of the same stuff while H was still living in the house. I tried to stay detached and GAL, but as soon as I came home and saw him there, I could not help but to be focused on the R and H. He would also have break-downs like the one you describe, and it made my life dramatic in a way that was very draining. Plus, when he was like that I would wonder whether he was re-thinking the S and then would be devastated when it turned out that nothing much had changed.
Although I did not want my H to rent his own apartment and move out, the peace I experience now is very healing for me and maybe for the R as well. We both have our space to think without distraction and find out what we really want. Plus now I know what it is like to live alone and I can make an informed decision without the cloud of fear or desperation. Not saying that I am never fearful or desperate, but I now know that I can successfully live alone, so I don't need to save the M at any cost, just to avoid lonliness. It's an enpowering place to come from.
This may not be the route that you need to go right now, but if you come to the point where you feel you need more space and that your H needs to have more consquences for his actions, just know that a physical S is not necessarily bad for your M. Maybe that's even a 180 for you? Anyway, I understand and good luck.
Mimi
M:37; H:37; M:10 years;T:13 years;no kids. Bomb ("I love you, but don't feel things for you I should":1/08/12 Separated (H living with various friends:1/18/12 Separated (H rented his own apartment:3/4/12