Advice on a curse to remove rival who is fairly strong witch

Im involved with a male for the last 2 years, he has another female and we know each other. I tried to work things out with him and her in a 3 way polyamarous relationship, and it didnt work out because she was very suspicious of me and jealous as hell. Shes blocked me in all ways on social media, but according to him is always asking how Im doing… When we still talked, she wold tell me that the only reason she accepted me in the picture was because she could see that I made him happy and had something that he needed, that she couldnt give him.
Me and him both come from more traditional backgrounds of one on one, but yet I know he is torn between loving both me and her. He cant let her go completely, although Hes told me he wants to be with just me in the future.
She is a witch as well as me, and I can feel that she constantly keeps some sort of binding and protection on their relationship. Ive seen it cause him emotional turmoil, so I dont do anything that demands a lot of his attention and time. The hold she has is causing him to be unstable in some ways.
I want to cause her to go away and leave me and him in peace, but not sure how exactly to do so without causing him any relationship potential damage.
She has a 9 yr old son, which i dont want to bring any grief to him for loss or harm of his mother.
Ive done a few binding spells, go away spells, and even so far as mental anguish spells, and she just seems to be able to deflect them like they’re nothing.
Looking for some sort of something that I know is multi layered that’ll remove her and her influence in our lives, without any damage to her son or to the man, or to mine and his relationship.

It seems to me you are getting got by this human male. If I were you, I make sure he had not cast love and binding spells on you. It seems like you are getting played hard.

I say do uncrossing spells on the whole lot and move away from this mess. You deserve someone that isnt into playing both sides to get what he wants.