Welcome! I'm new here as well, and my husband and I are dating a woman, so much of your post resonates with me. Eventually we'd like the relationship to morph into something where we're all together, but things will come with time.
If you haven't already, I'd highly recommend reading The Ethical Slut. It's a great book about polyamory, and while much of it is probably stuff you already know with your prior experience, there are some good points it brings up that might spark some good discussions between you and your spouse. Any tools you can have in your arsenal are good!
I wish you the best! It's a hard search (I TOTALLY agree about OKC- that's where we found our GF, and it's been the most fruitful place in general), but if you find someone, it's well worth the wait. It took us a good 2 years to find our GF, and we all mesh really well in completely different ways, and it's really beautiful.