There isn't a secret formula to meet people who are going to fit into your lives. Going to local meetups in your area and just talking to people with no expectations is a good way to start.
Triads that work are usually something people fall into rather than something they seek out. Many many couples who are new to poly are seeking exactly what you are seeking (I was too at one time). I've come to realize though that real authentic relationships can't be planned or controlled. I'd rather be in a happy V where the arms of the V are friends are really care about each other rather than being in a triad where someone involved is, for lack of a better term, taking one for the team.
Consider being open to relationships seperately, even if you still have the ideal of having a triad. The triad might happen but if you're turning down every person one or the other of you is connecting with think of all the happiness you'll be missing out on.
Everything will be ok in the end. If it's not ok it's not the end.