I am sorry you are going through this, ending are never easy but there are some things we can do for ourselves to lesson that hurt and pain.
I think you have a good idea about detaching because once you do your anxiety will begin to lesson.
You said you are seriously thinking about buying him out. I’d give myself time to think that through and end contact with him until you have reached a decision. You don’t have to answer your phone or even open his e-mails. Keep it simple and tell him not to contact you and in 30 days or 60 days (what ever you decide) you will have an answer for him about what YOU want to do with the home.
It’s hard truly thinking about what we want when they are in communication buzz. As you said he’s communicating more now then he ever did when you were together. You may need all that communication to stop so you can give yourself some time to decide what you want.
He doesn’t seem to be making much sense anyway.
I know for me when I divorced I wanted to keep my house and keep things as normal as I could for my kids. I changed things in my home so it was my home instead of our home if you know what I mean. In the long run too many bad memories even with all my changes and I no longer wanted to be there. I kind of stayed unhappy and miserable for 18 months until I sold that house and moved into MY own home.
I think if I had listened harder to what my friends were telling me I would have sold the house right away which would have broken that chain of communication with my ex and moved on to my new life right away.
Give yourself time and give yourself peace until you are ready to move on to a new life or resolve this one.