Remember that failure is an event, never a person.
I tend to agree that staying in the house gives you a better chance long term. I know in different situations different solutions are called for. I tried to keep my H here as long as possible and when he moved he was planning to come "home" on the weekends and sleep in th same bed etc. I might could have even worked with that, but his position of wanting a D (and other relationships) had not changed. I am worth more than that, much more. Make no mistake though, that staying in the same house is hard. I did it for over a year (and would still be doing it if he was saying he was confused or just needed space (not other R's).
You can do this. I liked Dom's plan for talking about one topic and night and then civily. That sounds like a good plan. I have to say I agree also with what having a parent move out does to kids. It breaks my heart to see how it's changing our D's.