Whats up with pg 18 chpt 20? Why did he not touch him?

Maybe because petting him like that is what a lover would do and they're not lovers. Maybe he's falling for muscles and doesn't want to admit it. (idk, just my best guess.)

I think that's it. He blames it on being sexually repressed from studying so hard (making me think he had to work extra hard just to into Muscle's university.

He's very much in denial.