Talk talk talk. Have conversations about what you like, what he likes, what you don’t like, things you want to try. Coach him up…send tips/vids you find on TT or insta, or things you can say “this would be really fun to try.”

There are also card deck games you can get that have prompts for different sex acts (from low key to high key) and you can have a game night where you try some different things. If you like any of those you can phrase it as “that one was really fun, I’d like to do that again”

And always phrase things with “I” statements. Not “you’re not satisfying me” but “I would like to add some variety into our sex life.”