Aridarr,
That totally sucks! And just like many others here, I totally understand what you're going through. For me, I met this one person online and I was like, wow this guy is an awful lot like me... very similar perspective of life, problems dealing with people, lots of self-confidence issues, etc. etc., and I wanted to be his friend. Turned out that he had AS (this all happened before I was even aware of the existence of AS, and thus before I realized I had it), but he was and still is in some serious denial. Denial as in, "I want to be normal, and it is wrong to be different!" He thought I was a freak for not leaving him alone, even though I only contacted him maybe twice or three times per week. What would be worse, obsessing over an NT who simply does not understand, or obsessing over an AS who actively puts down his own kind?? As an AS, he knew exactly how to hurt me, and he did it without a second thought. I was devastated about it.
I wish you the best of luck trying to switch your obsession, I haven't been able to do so quite yet. If you are successful, please let me know how you did it.