healing does take time. What's that song by the Supremes? You Can't Hurry Love, No You'll Just Have to Wait. Love Don't Come Easy, Its a Game of Give and Take.
My W is seeing OM right now after we S. She did it openly and told me about it. I think they may have had some EA type thing before S. It doesn't hurt any less. I wonder all the time if I can accept her back, but I know I still love her. I know she is turning to him looking for what I couldn't give her before. Emotional support.
It must be real tough to get comfortable and feel safe and secure again, especially after you've felt betrayed. I'm guessing this is what the WAW of mine is feeling. I betrayed her trust when I said I would honor and cherish her. So she is betraying me and our M.
IMHO, knowing that both of you have learned from this and have changed, knowing where each other has been and understanding that gives you both ultimate incentive to not let anything drive you apart again is an unbelievable place to be. I don't think it is as easy for your H as you think. IMHO, maybe share a little of your insecurity and see how he reacts. Maybe this will make you feel better, especially if he validates?