You asked how a dialogue with this man might look:
You: I want to talk about what happened when we had sex the other day. It seems to me like you were using that encounter to tell me that you wanted to be my only lover. Is that, in fact, what you want?
You: Ok. I hear you and I respect you, but that's not what I want. In the moment, I said yes to the idea of being just yours, because, as you pointed out, I was in a very vulnerable state. However, you deserve to know that I don't intend to hold to that. I prefer to make decisions rationally, like this, not in the heat of the moment, so if you want to make decisions about our relationship together in the future please talk to me like this. I'm going to have other lovers if it feels right, because that's what I think is best for me, and I would encourage you to do the same. Knowing that, do you still want to continue our relationship?
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.