How would you piece this?

[Mystik]

H has been living with another woman since May of 2009. Their lease is up soon and he has implied to me recently that he wants to work things out. I'm naturally feeling hesitant about his reasons. Is it because I have his son and he misses him, is it because coming back to me is easier than being on his own? Why does he want to work things out now?

He has set a date at the end of this month to talk, and I am hesitant to since he'll still have two months left of living with OW before anything can happen. He won't move out any earlier because he claims he is committed to staying there until the lease is up.

I know that H will suggest a three bedroom apartment together while we work on the marriage and work towards sharing a room again. I want to live separately and go through the whole dating thing again until I know for sure that it's going to work, I do not want DS to be hurt any more than he already has been.

So for those with experience, how does piecing work? Is it living apart and dating, living together but at the same time apart, or go back in with both feet to sharing a room, acting all couple-y? I've never done this before so I defer to all your experiences and wisdom.