Sweetie, here is a little thing you may want to ask your bf: how would you feel about me having another bf?
If he is cool with it, maybe you can get him to explain his thought processes in how he would be cool with it. It might help you understand him better. Even if what he says makes sense though, it still doesn't mean poly is for you. You have a right to choose.
However, given that your bf seems a bit selfish and immature, I am willing to bet that he isn't cool with it, and will try to tell you how that's different. It's not different in the least and you can call bullshit. Maybe such a question would help him understand what you're feeling.