Why would my husband join the same Facebook groups as the woman he had an affair with? [after cutting contact]?

[Shelly]

(repost due to a very nasty answer by babeheart)

So it's all over, after 19 months of cheating in 2008/9, and it only ended when I found emails between them.

These 2 went back and forth for months before he cut her off last summer, and dedicated himself to me.

There is an injunction on him, put in place by her, civilly not criminally, I might add - meaning he was never found "guilty" in criminal courts and I think she set him up.

At new year, he met her to tell her he does not hate her BUT that she's wrecked any chance that they "might have ended up together" or at least friends. I know she was devastated.

I now see that he's joining the same Facebook groups as her - then he deleted them all except one - and this one was one on which she used to write a lot of comments and do a lot of "likes"....then suddenly a few days ago, they were ALL deleted. He definitely joined those groups this month, then quickly deleted them just as quickly.

NB she has now set her FB settings to private and cannot be looked for on the search engine, making me feel that she has told him off for joining the same groups as her, he deleted himself, then she set her account to private.

Why is he telling her he doesn't want to know her, then joining her Facebook pages? I do not think he has her phone number. Why cut her off and tell her he's working on our marriage, and then cyber-watch her?