Bananafish, I wish I had an answer for you, but I don't. Looks like you are at a crossroad in your life and I wish you the best. Keep in mind, many others have been in your position. Me included.
I was lucky. I introduced the idea to my wife. She was taken by surprised by it and refused it at first. For almost a month, she was very quiet and wouldn't talk to me much. I thought we were heading to divorce.
Then, she started asking me questions about it. Her attitude with these questions started off derogatory, then slowly became genuine curiosity.
Long story short, that was years ago and she and I have had several polyamorus relationships since. The reason the relationships were numerous is because I was a pilot in the military. It was never hard to find a single guy (member of my squadron) to move in with us and be a long term, polyamorus threesome with me and my wife. However, the Air Force liked to move us around a lot.
If I was your husband, your admission would intrigue me, and I would definitely consider it. I have no problem with my wife loving another man. She is fully capable of loving more than one man at a time.
Good luck. I hope your husband sees it the way I do. I have no doubt all of us on this thread would like you to keep us up to date.