Welcome to our forum (sorry I'm so late in saying so).
Can I ask, what are your reasons for the pending divorce; is poly one of those reasons? Sounds like you and your husband are going through an awful time right now. I commend you for trying to keep it an amicable separation.
It's good for you to recognize your polyamorous nature, and to follow that path. If there's any chance you and your husband might stay together, make sure he knows about this change in your consciousness.
I hope Polyamory.com is of some help to you.
Love means never having to say, "Put down that meat cleaver!"