How do you spice your sex life up?

My SO and I have been together for 3 years now. We love each other very much and are best friends at heart! Except for one thing... our sex life. I have had long term relationships in the past but for him, I am his first long term relationship. He doesn’t quite know how to make a woman orgasm so I am trying to show him. I was wondering if any other woman have been in this boat of “teaching you SO”? We do have toys, he just doesn’t quite know how to use them. He also likes to be dominated. I just would like any new suggestions on how to spice things up or how to go about teaching him certain things?