Gotta, I'm following your story. I know you'll be better off without his negativity.
I wanted to address your question because I lived that life, too. I have asked him the same question "why did you have to be so mean to me while you were so nice to these women with no moral compass?" I've never had a satisfactory answer but have come to understand the following dynamic.
Do you know how your kids act like little jerks with you from time to time? They might have temper tantrums, or mouthiness, or any number of behaviors that make you want to scream back at them. Then you see other adults, in my case, teachers, telling me what a well mannered young man my son was. Meanwhile he was testing me on every issue. Literally, EVERY issue. They are rude to you because they know you will always love them no matter what. Those adults in their lives don't HAVE to love them, so they won't take the chance to be obnoxious.
Your husband and mine felt we were a sure thing. We MARRIED them. We were a PERMANENT part of their lives. We saw the skid marks, saw them vomiting, know all the gross sides of them. They are feeling bad about themselves and you can't help because you KNOW their secrets. So they feel comfortable being an asshole to us. I'll bet you had your share of love bombing after some of that verbal abuse.
These OW really, truly mean nothing. They are artifices. They are fawned over and admired in the high that comes from the forbidden. This is true in most infidelity, and I believe, doubly so when brain based diseases, bipolar, etc. are in the mix. Any OW is useful in this way. They keep the cheater from looking at reality.
And most cheaters are immature. They aren't ready to adult, to do what's needed to be a fully functioning parent/spouse. Asking them to participate as an adult invokes a childish reaction "It's not fair!"
I'll give you a small example. My husband and children taught/attended school in one county. I taught in another. Their school had a long spring break, about a week. I had Friday and Monday. Clearly, he'd be the primary parent for that week. I scheduled yearly physicals for that week, since no one would have to miss school. He blew a gasket. Wanted to know why "I" was planning things for him to do on his time off! How dare I ask him to do that!
Please try hard to get that image and those harsh words out of your mind, that you somehow didn't measure up. It's really their own twisted brains that has messed up.