diaphragms are not reliable when the guys are "large", as the cock tends to knock the diaphragm out of place. That's why IF you use a diaphragm, you're suppose to use a spermicide as well, which makes the pussy taste bad if you're into eating pussy, which most of us are. IUD's aren't all that reliable either, again, if the man is well hung, his cock tends to dislocate the IUD from the cervix.
15 years of the pill were killing her libido and ruining her orgasm. We got together as teens so she literally didn't know that it was her BC causing her loss of libido (and low level depression.) After going off BC, having a kid, and discovering her orgasm her sex life took off. Already being swingers, one thing lead to another and her sexual peak as we both round 40, I don't have the desire to fuck 3 times a day like I did when we were 19 and she's just too horny for any one man; even her guys agree they're tired.
My wife has either Nexplanon or Implanon implanted, I can't remember which. Effective for 3 years, no pills to remember, no weird spermacide aftertaste, no IUD, Sponge or diaphragm that a 10 incher can dislodge and a .05% chance of failure.
She does have some break-through bleeding between periods, which royally sucks but we're not 100% sure that's the BC. They expire this year, we're heading towards 40.... she says she's going to re-up but who knows, we might go the last few years before menopause playing the numbers game.
You're wife looks a lot like mine did in her 20s. I almost came in my cage from that statement. We've fantasized but decided economically it would be a bad idea to have another kid. I love my daughter but part of me would love for my wife to get knocked up by her first black guy, the only one she wants to with. It won't happen and it's utterly impractical for us but a hot fantasy. Good on you!