Not enough confidence

Hi everyone, I need some advice.

Me and my boyfriend have been together for nearly 3 years, and I love him to bits. But whenever we go to have sex, he tells me to do certain stuff to make him aroused.

I really want to do it, but something in my head makes me stop and try to avoid it. It’s been one of the things that have stopped me feeling sexy... I’ve never felt sexy even though he tells me every time he sees me.

I’m a big girl, on the podge side but he doesn’t care, he says he loves me for who I am and I feel so loved by him... but my thoughts are just all over the place when it comes down to the deed.

I want to be confident, and I want him to be shocked about me taking charge and show him what I want... but how can I change?

Please someone give me advice❤️