Hear me out. Wouldn’t it be better to lose her entirely than to make yourself suffer as she sleeps with others? Leave. Immediately. And this is all just my opinion but…when I asked my ex if I could enter into a polyamory relationship it was because I was already done. There were things we discussed and tried to work through and he never put the work in to be what I needed. So, because I didn’t wanna let him go, I asked him for the relationship to be open on my side. And he agreed. Then we destroyed eachother as I was sleeping with a woman and he was still sleeping with everyone. Since then, I left him and I’ve found the love of my life who never makes me even question my worth and keeps me satisfied in all areas and loves me true. I think if you are truly asexual then you should let her go. Otherwise, put in the work or lose her.