Deep breath! AGAIN!
Ok, now time to thing rationally about how to REALISICALLY make some changes within your life. Poly won't fix a broken marriage and from the sound of your fight, there is 10 years worth of resentments built up, likely on both sides. Unfortunately, the things said in a moment of anger, hurt and frustration will eat away at you for a long time to come if you both dont get things resolved. I would seriously start with repairing your marriage with the help of a marriage counselor.
When things between your husband and yourself are in a more stable place and possible with the help of the concilor, you can discuss poly again and how that will effect your lives. This is not an uncommon first response when a spouse feels like they've been blindsided. It likely brought forth all of your husband's insecurities and resentments. Most people don't deal well when that happens.
I've been married 21 years and have spent the last 2-3 years trying NOT to get divorced. Wen we started counseling, I truly did not see any way out, but we found it, but it did take a LOT of work on both our parts.