How to make a threesome happen?

Hey y’all. So my fiancé and I want to have a threesome. We both have talked about it a lot and it’s a fantasy for both of us. I identify as bisexual, but have never actually been with a woman and my fiancé has only been with me and one other person so he wants a chance to experiment. We both want someone that we are comfortable with, but it’s really probably gonna be a one time thing. How do you go about finding someone to do that with? We tried looking through our not-so-close friends and making a joint tinder, but as of the last 6-8 months nothing is coming up. Please help!