Your post brought tears to my eyes. I rem feeling exactly the same. I went through the same thing except I left the place and still think about the other woman ( plz don't do it for as long as I have).
It's absolutely rotten to feel as we have felt/ feel and you are an absolute queen for still exercising and working.
U just have to go through those feelings hun and hang on. It's a roller coaster but I just know you have what it takes to get through to the other side.
Write it down, talk about it, I call life line 131114 to talk/ vent, cry it out, scream it out. Go out with girlfriends when you're feeling stronger.
Place your power and value in yourself not him. Now it's your time to find who you truelly r and to get through this rocky stage. It helps to have loads of support and I truelly hope you find that.
Sorry this guy was such a douche. I'm 36 & have had my fair share of them trust me. Ask any woman and they'll tell u the same.