Is it bad that I just want my Ex-girlfriend as a fwb

I don’t know why I just want to hookup with my ex.
I know that she will say no to this but I can help craving her. I don’t want to date her but I want to be sexual with her. I don’t think that we had the best sex but there is something that I miss a lot her body. When I get horny all I do is think about her. I don’t know what to do to stop thinking about her in that way. We don’t even speak anymore. I couldn’t take just being friends 😭.