Anytime a cheater continues to work with the OM/OW after the affair, it will continue to be a trigger and delay your healing.
I even advised someone whose GF discovered the affair and decided it's over, to still look for another job if he was serious about wanting her back.
People have sold up and moved house when the AP lives closeby. It hinders your healing. I remember one woman asking her H, how he would feel going passed the house of a man she'd had oral sex with everyday. How was she expected to get over it. It's not much different to your H and her seeing each other daily.
Her telling your H is like asking him to keep you in check. Like how dare she approach me and call me out on my affair with her husband.
I'm wondering why this suddenly means colleagues will know if they didn't know before.
Him continually putting her feelings above yours is worrying.
If I were you...is keep a journal. ..make notes of all the times this has happened. Record your feelings and any times he's actually comforted you and shown remorse not regret.
We can all regret thingd...but until you are truly empathetic... you aren't capable of remorse.
In my experience it's those who never had any fear their betrayed spouse would leave them...that don't show remorse. He can act how he likes, safe in the knowledge that you'll be there.
His actions are showing he cares the least...and that gives him the power in your marriage.
Consequences follow poor behaviour...He hasn't had any.
I suggest you focus on yourself. Increase your social circle and consider a new interest first yourself. Be the best you can be for yourself. Treat yourself to the things you like as much as you can.... if that's massages...spa getaways...then do that. Exercise or keep exercising...as it's good for the body and mind.
You need to gain personal strength for whatever the future holds.
When you want to discuss the affair with him...write your feelings down instead. After sometime you can reasses how often you've needed to talk and haven't.
Your strength will guide you through this.