Attempt at piecing????

[addie]

A week later he told me that he moved there because OW didn't want to be in a relationship anymore.

In talking with XH, he said that OW has been persuing him via phone etc. but that it was finally over last Wed.

These are some things that jumped out at me when I was reading your post. The first one indicates that it was OW and not XH that no longer wanted to be in the R. The withdrawal process seems to be much more difficult when it isn't WAS that comes to the realization that they should leave that R. The second quote indicates that there is still contact with OW. This means the withdrawal process hasn't really begun yet. Every time they make contact, it starts from scratch.
XH is definitely rebounding and testing the waters with you. Be very careful not to jump into this with both feet.