Sounds a lot like you need some time out... I would hope your husband respects your relationship enough to give it to you - to me given the huge differentials in your posts... you NEED him to (for a defined period) give you and your relationship absolute precedence... particularly if this woman is to remain your metamour...
You are absolutely entitled to time and space to adjust, and have every right to ask for boundaries that SUIT YOU... not them... (again with a defined period). If that goes to the extreme that he isn't to see her for a time - then that is fine... whatever it is that YOU NEED to deal with the losses you are feeling, and then start moving forward together at your pace.
Sorry you are feeling so much pain and anger, it truly sounds like he is not handling this very well, even if he is being compassionate - he is NOT giving you the time and space from her/attention from him that you obviously need to deal with this situation.