Hi and welcome
Your situation is becoming quite common - bi-sexual people wanting a partner of each gender at the same time. There is a blog called A Hot Poly Mess
written by three bi-sexual women with husbands. They haven't posted this month but there is a large body of work that you might find useful.
Does your husband know anything about polyamory? Is he interested in learning? I think if he loves you for who you really are (and not who he thinks you should be) he would do some research. Here is a very good place, also the polymono group at yahoo and my blog might be useful.