Insecurities and Sex❗️😩

Soooo I have this insecurity with being on top... so I feel like it just isn’t good for him or it’s bad when I’m on top. He says I am good and he doesn’t care that I don’t go on top a lot but I feel really bad for not and I want to go on top but when I actually get on top I get really nervous that I’m doing bad... anyone relate or just like advice on helping with insecurities😩