whyme --
I do know a woman who had just such a reconciliation agreement with her H -- they had just a few basic points. They remained married, maintained separate households, and had sex only with each other. They saw each other once a week, phoned once, I think. Otherwise each led his/her own life.... that lasted something like 2.5 years; he then came home....
It worked well for them; she recognised the depression. He had had an A; BD was only after it had been over for a while.... Her one boundary was "no one else". He made no promises, but did hold to that, and slowly worked his way home.
It's an interesting concept, one I'm not at all against.