I dated a guy with aspergers once and I must say it wasn't exactly like some of the doom and gloom posts in this thread. Sure, there were issues, but nothing like what is being described. Though I say that without trying to assert that I expect my experience to be universal.
He was incredibly sweet, very sociable (in the sense that he approached people very easily, even if he wasn't good at it), and he was very much into me. He was out of town often for work and whenever he returned, like any other boyfriend, he was very much interested in spending as much time with me as possible. We went on vacation together, road trips, dates, cooked together, etc. When he mistakenly broke a valentines day gift I gave him, pretty much five minutes after giving it to him, he was incredibly upset. In many ways, he was just like any other boyfriend except for some of the quirks I had to get used to. Most of them were pretty easy to deal with, like the fact that he would speak increasingly loudly without realizing it. We could be in the car together and he'd essentially be shouting while talking to me. Or the fact that he would break or damage things pretty frequently (not intentionally).
Really, the "problem" was physical affection, not emotional. He did not seem to like sex or even being naked. As a male who has hated how skinny I am for my entire life, I very much need to feel physically comfortable, especially when naked, with someone I'm in a relationship with. That was not going to happen with him. Since we never talked about it I have no idea if that was related to him having aspergers but it was something I was not able to get used to. Our relationship felt very much like we were really good friends, vs. boyfriends, because of the lack of physical intimacy.
It didn't leave me scorned or bitter and quite frankly after he moved away we continued to communicate for awhile and he seemed very attached to me.
Would I do it again? Absolutely, because people are different. Just because it didn't work with him doesn't mean it wouldn't with someone else. Just because it didn't work with me doesn't mean that he'll be alone forever. I would be very hesitant to solely blame aspergers for a failed relationship, at least to the extent thats happening in this thread.