NewMama, checking in late on your "Fears" posting.
Yes, all those things could happen. But they aren't happening now. Quoting Byron Katie here: the stories we tell ourselves are so much worse than the reality will ever be.
I told myself there was NO way X would ever sell the house to me. But he did (or will, assuming I get the mortgage)
I am not downplaying your fears. They are real, and they can be paralyzing.
BUT WE DON'T KNOW THE FUTURE. If your H breaks up with OW at some point, who knows if you will really be "torn" by that time???
As down as I am, sometimes I have to say: well, my present is sucky enough. Why torture myself imagining an even suckier future??
I don't know if that helps. This is soooo hard, we all know that.