I need help... I don't want to lose my relationship..
I (31f) have been together with my partner (31tf) for three years now, it has only been about six months since she had come out to me as poly with another already in mind. In the past I had been used, ex's have abused being poly just to cheat on me or leave me after they had gained their partner. I had panicked because of this, however I wanted to try to learn to accept and to even just be okay with things. To trust that she wouldn't leave me. She hasn't, however a number of issues have come up, resulting in is fighting often now. At first it was the fear, because along with this addition to our relationship that person also had a partner. There was also another girl that my partner had developed feeling for and wishes to have her join. (Basically now there are three other women she has developed feelings for.) I felt overwhelmed.. hurt and confused and it left me in mental spirals. The biggest thing due to my trauma is the result of sexual desire, particularly with one girl. I couldn't handle the thought of her being with someone else physically, especially while trying to get used to all of this. But they send hentai (anime porn) to each other. Sext though they don't send nudes. It.. leaves a heated knot in my stomach.. a voice in my head wondering why I get ignored in messages and constant accusations.. I've tried comperson, tried to be okay and breathe. Talk through my emotions and jealousy.. my partner and I used to be so close.. now we fight like cats and dogs. My anxiety is so high that I constantly think about them together and it drives me insane.. it's like someone is screaming at me in my head with a megaphone. "They could be getting spicy again. Just lying and downplaying it. They've already texted while at work. No matter how much you whine it's just going to happen again. And again. It's inevitable."
I hate myself for it. I hate how I am and I just want my partner.. I don't want to lose her.. she doesn't want to lose me either.. aside from therapy and doing myself up with meds for anxiety and depression.. I don't know what to do.. I'm so scared and terrified.. how do I overcome this.. how do I stop the thoughts and just be okay with her wanting to be with others.. I've done so much research and video essays.. writing my feelings out and trying to tell myself it's fine. She still loves me.. I feel like rot.. I feel like if I can't rewrite myself and get out of all this negativity I lose the only light I ever truly had in my life.. I just don't know what to do anymore and I'm so scared..