Most people aren't secure enough with themselves to be with anyone with a "problem". In society, you're really not supposed to associate with anything that others might judge you for. It's annoying, and I wish people were stronger, but they're not.
If you're dating someone that would break up with you over your condition, maybe you shouldn't be with them. Or maybe you should, but just casually, and never confide in them about aspergers, unless it starts seeming like they might be okay with it. It's okay to be less than honest, remember that. Being totally open about things is only doing you a disservice, even though people say honesty is the best policy.
I remember how I recognized someone at the gym who went to the same college I was attending. Her sister was in a wheelchair, and hung out with her and her friends, but she fearfully denied any relation to said girl when it came up. I later did find out I was right the first time, and that was her sister. Why would she deny that? Probably because people might think less of her.