Bi-curious, Looking for my first Girlfriend!

I'm 25 years old and am currently engaged. I have never actually been with a girl but I have thought and fantasized about it many times. My fiance (who I've been with for 6 1/2 years) and I have talked about having a threesome many times but haven't found someone "we" (mostly me) are both comfortable with doing it with. I guess you could say I was or am a little scared and a very shy when it comes to this kind of stuff. So we then entertained the idea of me maybe getting a girlfriend or really just someone i can connect with that will understand our situation. And maybe me and my fiance can both have our fantasies come true. I could really use some advice on what and how I should go about starting to look for someone like that. Thanks 😊