Hi,
I'm a long time DL (not AB) and live in a solid relationship with a girl who shares the fetish. We are both in our 30s.
I was touched by your post. Really. You surely lovey your BF dearly. And you are truly concerned about advancing your realtionship. That's good. No realtionship will withstand a sexual frustration of one person for ever, i.e. you not being able to achieve an organsm, for the reasons you described. I will get orgasms both with or without me wearing diaper. And I do enjoy plain sex, too. Its all in the brain. I get off by imagining I'm doing my play with someone else than my GF, while fantasising about it alound with (!) her. She'd tell me I'm being a naugty boy cheating on my GF, while making sure she wears hear dipaer just loose enough to eventually facilitate penetration. She'll usually have an orgasm before me, giving me the delicate choice of wether to cum inside of her or inside my diaper. You see, its not so much about the visuals and the aesthetics, but about the play with the unspeakable. And thinking and speaking your wiredest fantasies. I suggest you go sit on his face, wet your diaper in a huge gush of warm pee, make him feel the warmth in his face through the plast and watch his wiener grow to a treetrunk. Just before he is about to come (BTW does he relief himself usually or do you asist?) you make sure you slide that salami in youe wet pussy, by any means. You might want to talk to a female about those orgasms, I'm being told stories that most women do not achieve vaginal orgasm at all, unless there is extra stimulation of the klit. If that's true, you might want to find about what type you are.
I don't know whats going in your BF's head, meybe it has helped you a little to learn what is going on in mine. You'll get it, for sure.
Cheers,
the Corporal