1 30F have been engaged to a 31m for 1 year and dating for 3. I want advice on how to explore a sexual fantasy with a woman further.

We have a wonderful and healthy relationship. We are both in therapy and attend couples therapy regularly to help better our relationship (not for any particular situations). Our therapist has had us working on our sex life and becoming more open and honest about fantasies, porn, porn usage, e.t.c, so both he and I have gotten to a point where we openly discuss what we like to watch and fantasize about. We occasionally watch porn together. So about a year ago, we were having sex and he was going down on me and I mustered up the courage to tell him I have always fantasized about being with a women and have her go down on me. He was super supportive and asked a lot of questions like will he be there, etc. We agreed we weren't interested in threesomes or an open relationship at this time, but solely I wanted to experience this sexual fantasy. We talked about it with our therapist and he gave us a lot of advice before we decide to really just go for it. I feel like I'm ready for this to happen but l'm not sure where to start. Where do I find someone? Should it be someone we know or someone that is potentially in our city? Do we find someone online? I don't want to broadcast my name or identity to find someone. I'm not sure where to start. I also am not sure what to even tell someone? Like is there a name for this particular fantasy: I want a women to go down on me and my partner to watch? I'm still super new to this so please be kind and I'm really just looking for advice on where to go next. Thanks all.