He may have been scared of her reaction to seeing him with his ring on. It sounds like he made the decision to return home (in spirit, not in body) long ago and is just now feeling that he can do it all the way. He might have been scared of upsetting her. You know, it sounds on the surface like a jackass thing to do..to be scared to upset your girlfriend and not your wife...but I'll bet he feels a tremendous amount of guilt for voluntarily accepting someone else into his life and then leaving them in the lurch, in the end.
Putting the ring on may have felt like he was rubbing it in her face, prior to last weekend. Once she told him to never contact him again, then he might have felt safe in wearing it.
Who knows, who cares!!!!
He is back and is back in full force it sounds like.
I am so happy for you!
P.S. I wouldn't even worry about the romance right now. Just do whatever feels natural and continue to be the upbeat and loving person that you are. Then when the dust settles you can get a better picture of what would work in your new R!