I don't think you're crazy -- you love your husband -- but I do think that he has a sexual addiction, and until HE decides that he needs to get help with that (and does), I don't think there's much you can do other than protect yourself and your child. Even he told you to do that.
I am a child of an alcoholic myself, and I don't think your husband is really going to change until he "hits bottom" here, I really don't. Serial infidelity and sexual addictions are way beyond the scope of this DBing forum, and really beyond the help of us amateurs.