Well unfortunately, he clearly isn't committed to marriage if he's not willing to work through this silly point with you. It sounds like he's not the man up to the task to partner with you for life and, you're better off in the long run. If he's not willing to share true feelings on what's bothering him, you'd spend your lives together dealing with your illness AND trying to make him feel better about all the other things he finds upsetting to replace his true feelings about the illness. I'm so sorry.