I think it sounds like you are putting a lot of the blame for his affair on yourself.
" I’m so much more comfortable being used and unappreciated. Something my husband refuses to do for me. "
It maybe true that you have difficulty accepting that you are lovable. But he didn’t refuse to "use and not appreciate you" his PA was absolutely an insult to you, at any rate that’s exactly how I felt when my H had an EA, used and taken for granted.
You speak as if it was some sort of self fulfilling prophecy, that he would cheat on you because you never let him love you???
I get it, I did it too. I still struggle with the idea that if I was good enough he would not have done this to me, If our love was strong enough, real enough he would not have been able to do this to me. But that’s just carrying the shame of his actions.
I think it’s so painful and even life threatening to know you can be discarded by the person you rely on for your survival, that we turn the blame on ourselves because it gives us the illusion of control. I realized in therapy that I blamed myself because I was afraid I didn’t exist without my relationship.
You are rewriting your story now, you have to because your reality has shifted, maybe even been destroyed. But you get to write this story, be choosy about what you put in it. "this was all my fault and he really is the amazing caring man I thought he was" may feel comforting right now, but it’s way less than you deserve.
Peace and happy soul hunting.