Sex is to please both parties. Switching is not difficult and a healthy part of a relationship, so if it pleases him, I would talk to him how it doesn't please you and ask what part of being on top pleases him. There are more than one position to be on top, and since you are still new to sex, experiment with different positions to find which you like. It could just be you don't like to be on top with him, you may feel differently with other men.