I know I'm posting a lot at the moment, just trying to get it all out. I will start reading and contributing to other threads too.
I've become good friends with a woman around my age who works with H. He is a store manager, she's the assistant manager. When I confided in her that I suspected the OW was a 21yo casual employee of his, she agreed and said it is a badly-kept secret around the store.
OW has worked with H for two years and their relationship became noticeably suspicious - to the point where other employees commented on it - just prior to BD when they attended a work party together. My friend said that their relationship since BD has been very inappropriate - locked door meetings, favouritism and special treatment, messaging each other when he's in the office and she's on the shop floor. She said that a number of employees are ready to file a complaint with HR over it. H is on thin ice here. He could lose his job because of the imbalance of power between their positions/ages.
I met this 21yo at a work function a few months before BD. I has brought S1 along to support H. I immediately disliked her. I thought she was fake, snotty, rude, and bratty. (My friend said her nickname is Sourpuss at work and she is not well-liked. H's nickname is Teflon. What a pair!) She was there with her long-term partner who she dumped just prior to H's BD. It's a relief to finally connect all the dots, as cliche as it is.
I'm not threatened by her at all; in fact it's almost laughable. I'm a 31yo university-educated professional woman with a six-figure salary, a mortgage, and a child. She can't compete with me.
H doesn't know that I know who the OW is. While I don't give a fig about her, I'm struggling with my feelings about H. I'm finding it very hard to look him in the face or feel anything other than disgust. I'm pretty good at faking it in written communication, but until I can control my emotions in his presence, I need to be NC. I'm pretty detached from the outcome of this situation and I don't really care if NC helps or harms our relationship at this point. NC is to protect myself.
Sidenote: My friend also said that up until a few weeks ago, H was actively deceiving his employees by making up stories about doing family activities with S1 and I on the weekends as if everything was peachy. He stopped wearing his wedding ring the night of BD and his employees had all heard through the grapevine that he had left me, plus the obvious relationship with OW. As a result, they have completely lost any respect or trust in him due to his lying, deceitful behaviour.