everyone's idea of what is okay and is not okay differs from relationship to relationship.
some men are okay with that and have no problem with it - others do.
what you need to do is sit down and have a serious talk with your husband about the boundries of your sex life. make sure that both of you have an understand of what is and is not okay. It's not okay to fool around with either a male or a female if it hurts your husband.
if having an open sex life is important to you, then maybe you should rethink the basis of your relationship, and either attempt to work something out with your current husband, or pack up and leave. I know it sounds harsh, but sometimes you realize things about yourself later in life.
you can love someone - but that doesn't mean that being with them is what's best for you.
there is no "right" or "wrong" there are just differences. talk with your husband to find out what will work best for the BOTH of you.
good luck!