Don't take the breakup as a downer, but as a blessing.
You found out early that he is not accepting you for who you are.
As I tell my girlfriend that her RSD is part of who she is. The RSD has made her stronger and more mature and open to new things.
Now would you want to date someone who can not accept you for who you are? What happens fruther down the road when you get married? How would he deal with marriage, children, and RSD? Would he be there for you and children then?
It sounds to me that this guy has a relationship issues. This has nothing to do with your condition. A real husband/father will not use any medical condition as a excuse to not take responsiblity.