Do you have any reason to suspect your H is still involved in any way with OW?
Are there any strange signs? Do you feel it in your gut?
Has your H done enough, in your opinion, to reassure you that he and OW are over? Has he spelled out why in fact he is home now and not with OW?
What I am getting at is, are your fears general and irrational, or specific and related to evidence?
In one for the DBing books, either DR of DB, Michele talks of a couple being instructed by their C to schedule two one hour sessions a week in which the W could question her H about his affair. She was not to talk about it outside this time, and he was supposed to answer any question of hers fully and honestly.
At the first session, W asked lots of questions, and H was patient in replying. H even allowed W to go over the hour limit. After that session, W felt no more need to have another. She felt H had opened up to her and reassured her, while H felt that W wasn't going to spend every waking moment questioning him and reminding him about his A.
Perhaps you could institute something like that between you and your H?
Hope this helps.
Livnlearn
"The unexamined life is not worth living" - Socrates