Gaydar = your own ability (radar) to tell if someone is gay. this doesnt seem to be the problem though.
If he doesnt masturbate and isnt interested in porn then that is possibly an aspergers thing or else he has next to no sex drive.
You had good sex at one time, why? work that out and talk to him about it. If you slapped the brakes on because of guilt, his aspergers may trap him into that mode until you remove it from him again, that may take some time and lots of reassurance that the good times can and should roll again.