You can't know whether poly will really work for you or not until you try. But you CAN find another mono partner even if poly doesn't work for you... your husband is not the only possible person in the works with whom you could bond, I guarantee it. If you've been thinking of leaving for years, maybe you just should. It certainly doesn't sound like a happy marriage. Show some courage.
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.