Get out! Run! There is no relationship with an Asperger or Autism sufferer. You can think you have a relationship with them, but they are completely unable to have any relationship with you, care about how you are or have any ability to gauge your mood. Carry on if you will, but it is doomed.
That's not true. People on the "autism spectrum" can have feelings for other people and they can care about other people. It is true that they have trouble gauging other people's moods and reading ordinary social cues, particularly perhaps ones that are conveyed (often subconsciously) by facial expression or ordinary body language. But to say that they can't care about someone else is neither true nor fair.
That said, it can take enormous effort to maintain a satisfying relations with someone with Asperger's disease or autism. Some people will do this better than others, naturally, partly because some people have a better developed "emotional intelligence" than other people, and some people are generally more flexible about what they want/accept from other people.
To the OP: I think I'd try initially to look beyond the particular to the general - for example, the real problem is not that the person with Asperger's doesn't send you text messages but rather that he or she doesn't think to communicate with you when you're not together. This doesn't mean that the Asperger's person doesn't care about you, or even that he or she isn't thinking about you, but rather that all of this doesn't translate into the sort of action that we might expect.
Having said that, when talking to people on the autism spectrum, you might need to convert back to their way or thinking, that is, go from the general back to the particular. "You don't communicate" may not mean much, whereas "You never send me text messages and I wish that you would" is a much more concrete way of putting it.
Of course, the autism spectrum, which includes Asperger's syndrome, is just that - a spectrum, and some people are much more severely affected than others, obviously.
Anyway, good luck!
