I doubt his issue is hormonal although it is possible. I did a little research on Aspbergers upon reading your thread, here is a good link describing the symptoms although I'm sure you've already done considerable research http://www.activebeat.co/your-health/10-symptoms-of-aspergers-syndrome/ but reading those symptoms myself does seem to correlate with his behavioir.
Sabin claims the average for having sex is once a month for married couples - I find that hard to believe. What are those statistics based on? Eighty year olds?
I've been married for almost twelve years, am forty-six and I'm still like a rabbit. The average man's testosterone starts to decline in his late twenties to early thirties and many men need testosterone replacement therapy by the time they are in their forties in order to maintain a healthy lifestyle. His issues though do not seem testosterone related to me but psychological. Also as Sabin mentioned, stress can be a problem affecting a man's bedroom performance. You said he has spoken to a doctor - is this doctor a therapist? If not I think a psychologist/psychiatrist may be the way to go.
Obviously you are a very affectionate and sexual person and like myself, sex is extremely important to me. I personally couldn't imagine being in a relationship without regular sex. As WitnessMyFury asked, how was it you didn't pick up on any of these behaviors prior to your marriage? Or did he suddenly develop these issues after marriage? If that is the case then something is definitely strange about the whole thing.
Don't give up on your relationship until you have both at least made an exhaustive effort to figure out the problem and work it out. Keep us informed!