I completely understand your head space. It's a difficult situation. You never want to to feel like you have had to 'persuade' or 'push' someone into something, especially something that is as personal as this or any other intimate or sexual preference.
However, the flipside of you opening up to him is that you may end up 'introducing' him to something that it turns out he is open to, that you now both can share as part of your already amazing relationship...
And the best part about that outcome is that, if you go on that journey together, and you are open with each other, there are no rules set in stone about what happens from there. He may choose to be more voyeuristic, and be happy with you pursuing things further (but openly together) or he may dive in the deep end with you and you explore all facets of this world. It won't really matter by that point as you will have an open and honest relationship and no longer hide your desires!
I wish you all the best with everything