I understand what you are going through. Your hubby will never understand this illness due to his ignorance. Make an appointment with the doc your hubby goes to, one that he trusts explicitly.
Beforehand tell the doc's office you need an "in the office" visit to talk to the doc, not a medical exam visit. Tell them the doc needs to discuss this biological illness with hubby. Tell them to please use pictures to show how the chemicals are imbalanced and how the medication works to correct it. If your hubby is a visual learner that is the only way they will make an impact. If hubby thinks all disease that does not effect the body where it can be seen then ask him to explain diabetes, or cancer, or some other illness that cannot be seen.
If he trusts this doctor he will have to decide whether to believe him or not. This doc is not a psychiatrist or a therapist but HIS doc, someone HE trusts.
If he does not understand this from a medical point of view then there is little that you can do to make him understand and you'll have to decide what to do at that point. You are young and this will be with you the rest of your life. As time goes by they will find new drug therapies that may or may not work miracles in your body. How do you want to spend those years, arguing with hubby about this or living without his attitude?
One of my old friends had this and she suffered daily until she found Depakote. It was like a miracle to her. She is such a different person now. I hope you can find a drug therapy that works well for you soon. She also got rid of a hubby that was mean to her when she had bad days. She felt so much better after he was out of her life, she didn't realize she was having other things, like environmental depression, too. She was so much better after him.