I think an frank and open conversation might help. Ask him what fantasies he has, what things he would like to try, let him know you won't judge him or become upset. Each of you might have some things you want to try that the other one isn't interested in (or won't do) and that's OK. But communication is key, the hard part is getting him to get past being embarrassed by the subject and to truly open up on what he wants.

You try some of the things he wants to try, he tries some of the things you want.