I agree with most of what everyone else is saying. I would add to look at your choice with more gentleness and compassion for yourself. You must choose what feels right to you. We should be no more eager to tell you to choose polyamory because it is the choice that we've made than we are to tell you to stick with monogamy. Only you can weigh and net out those things.
I've thought very hard about adding another minority status to my already complicated existence. It is definitely hard being a sexual minority. It is plain hard to be different. At least in my calculus, this didn't outweigh the difficulties I would find in terms of my own life satisfaction in leading a monogamous life.
Your calculus is different. That's ok. Your (and my own) calculus may change down the road. That's fine too.
What's important is that we're actively choosing what feels right to us. So, I congratulate you.
Male, Straight, Poly
“Instead of getting better and better at avoiding, learn to accept the present moment as if you had invited it. And work with it instead of against it. And making it your ally rather than your enemy.”