One of my first forays into poly was with Dreamy, a really hot guy I met online. I started out telling him that I wanted to be completely open and honest with him. We would share our dating stories, usually while in bed. There were times he'd say to me, "Are you sure you want to hear this?" and I said, "Yes!" I let him know that I really wanted to be able to communicate about sex and relationships, and so on. Of course, I still had moments when I did feel a bit awkward myself, but I would acknowledge those feelings and let them go. Dreamy actually expressed relief at being able to talk about this stuff. If let your partner know that it's new for you too, but that it's important to you to be able to say what needs to be said, then you two will be able to find your own comfort zones together. You don't have to share all the little details, and be mindful of when it gets too uncomfortable, but if you show ease in being able to talk about dating others, at least, it might make him feel ease at listening.
There was another guy I was seeing (very briefly) who was really not okay with my wanting poly relationships, and he was resistant to hearing anything about it -- I had to be super pushy about getting him to listen, and eventually broke it off because he really wanted us to be mono in the end.
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "