Since right now you say you're just interested in finding out more to see if it is something that might work for you, I would tell your husband you've been thinking about how happy being with women used to make you (assuming you are going to focus on just finding a woman(en) at least at first) and see if HE will find out more WITH you.
Personally, I brought up polyamory with my husband as soon as I had the thought/feeling so that he could get used to the idea with me. The transition was much easier because we were both growing together - even though I was ready sooner, he felt included in the decision and was ready to support me in any way he could. Granted, we were already sexually open so this wasn't too far of a jump.
Regardless of the situation, all you can do is bring it up, help him learn more while you explore, and see what needs to happen next to try to make your life more fulfilled.