In this stage of the game I fall back on the advice of our mediator: know what YOU want. You cannot negotiate with anyone unless you know what you want.
You want to stay in the house. Push for that. I wish we'd been able to do so. In my case I had to choose between son's school, the house, and the damage exh was willing to cause.
I wouldn't approach him. Let it all be done through mediation.
I'm not sure I would hold back, but you have to trust your instincts on that one. You know your stbx better than we do. Trust your gut.
Does this help? xoxoxo
M 20+ T25+ S ~15.5 (BD) BD 4/6/15 D 12/23/16
"Someone I loved once gave me A box full of darkness. It took me years to understand, That this too, was a gift." ~ Mary Oliver