I think a lot is going on in your head that you need to get out and discuss with others so your imagination doesn't take over completely. You aren't checking out what others are thinking and feeling (your ex-T and any future T) but just assuming stuff in your head and going with it. You are creating a closed loop in your thinking.

You are feeling! You can't escape that, hence the SH and feeling like you are split, etc. You are just not confronting and looking at it with someone so you can triangulate it and see it for what it is and work with it. If nothing else I would get a notebook and write out stuff, the "details", and look at them as if they were about someone else, a case story in a book sort of thing?