I have been in your shoes and am really sorry that you are having to go through this.
Years ago, my ex (then boyfriend) had an old girlfriend that he had cheated with on every other girlfriend he ever had. I remember asking a sponsor in Naranon if it was unreasonable to ask him to have no contact with her. (My ex was a trying to recover crack addict). She said "honey, there isn't ANYTHING at all reasonable about your situation and you are entitled to say/want whatever you need to be in the relationship. Just be able to name the consequences and handle them".
What in the world makes us "love" someone that cheats on us and causes us untold emotional drama and trauma? I struggle now to believe that that really is any kind of love. I know that for me, I had become addicted to that relationship and that man. In my opinion, love is kind, true, respectful, loyal, and honest. A relationship might be many things but without those qualities I'm hesitate to believe that that is any sort of "love" that I want to be part of.
It sure took me a really long time to realize that (like years) so I understand believing that feelings like you are having are love....maybe it's chemistry, attraction, etc. but love is when there is mutual concern and caring.
I began to look at the broken parts of me that made me believe that I didn't deserve better. I'm not saying that is the case with you but it did help me to ask "why do I believe that it's ok to be be treated this way?"
I can definitely understand why you want to quit the roller coaster ride and hope that you will consider doing exactly that. You don't have to stop your feelings for someone when you take a seat further away from the fire.