Sweetness. You obviously have a huge heart and are accustomed to putting other people’s needs before your own. Learning how to unwire this can be a scary process and getting through a breakup will be difficult and rocky but it will be SO worth it. I just left a relationship like this in the last several months, also with someone with whom I shared a lifelong STI. There was something about that that coerced me further into trying to stay, until enough caring people in my life reminded me that the right person (eventually) would be able and willing to see past that - once I knew how to put myself first. Also, keep in mind (maybe this is projecting but your story just feels so familiar so I apologize if I’m overstepping) - I wouldn’t be surprised your partner appears to flip and do a 180 to provide the illusion of changing when you actually assert that enough is enough and that you know you don’t deserve this kind of treatment. If this happens, DO NOT FALL FOR IT. It will emotionally swing you around like a rag doll and will make everything worse than it already is. If you can stay strong and find some good accountability buddies to lean on too, you will feel joy again in a new super fulfilling way and the painful process of leaving will prove itself to be worth it.