Welcome to our forum.
It sounds like you are in a really tight spot with your boyfriend. You don't want to lose him, yet polyamory is very important to you, and he is unaccepting of it. Something's got to give. Either you will have to cut the ties, or address him again with it and take the risk that he will cut the ties. If nothing gives, you may end up in a life with him in which you always feel a little out of place, a little resentful, and forced to hide your true feelings. The only way of getting around that is if this "poly-ness" is just phase, and you end up being content with monogamy. I don't know if those are good odds to bank on, though.
Perhaps we can help, at least as a listening ear, if nothing else. There are lots of valuable threads to read here; have a look around. Post any thoughts or questions you may have as they come to you.
I hope you and your boyfriend will be able to work things out.
Love means never having to say, "Put down that meat cleaver!"