Getting your partner to understand and support is both the most important and hardest thing you can do. Give him some literature.
At the same time, your happiness is your responsibility and comes from you. If you cannot cope and feel you need medication, don't feel shy or guilty to set up an appointment with a doctor for an evaluation and script. You sometimes need to be selfish and at all times remember you do come first. You first need to get YOU right before you can contribute towards a healthy relationship.
Give your husband some literature to read (There's plenty on the internet you can download). Sometimes having a professional diagnosis makes it easier for the other person to accept that you "aren't making it up" but that there really is a chemical imbalance and you are seeking help to rectify it.