I had to snicker that OW referred to you as "Saint SJ." It seems her ego can't handle the fact that you were not threatened by her (meaning you simply let him go and carried on with your life) and that he ended up leaving her anyway.
So she's twisted the fact that you are a kind and reasoned person into a negative, while she threatens self-harm... Yet somehow she thinks she is superior to you.
Hoo boy. The threats sounds like someone with borderline personality disorder. They tend to be dogged to avoid feeling abandoned and to not to respect boundaries, so hopefully she finds a new place to focus her attention. I hope your H realizes this is not a healthy individual, and he should avoid being alone with her, not only for your M and rebuilding trust, but because she is the type to come up with false abuse allegations against him. If she is in his office, he needs to leave the door open, and make sure she is never able to corner him.
For all of these reasons, it may be better if he is relocated. She's likely not a healthy person who will just let it go and move on.
You are doing well and your H is showing remorse and a willingness to put himself through discomfort to help heal your M. I feel very positive for you.
