The mangaka does a nice job with visualizing and writing MC's desperation to remain respectful while he's alone with a girl and that even very nice girls are always asking for a level of touch that turns the average boy into a rabid dog. Ah, youth.
For anyone who thinks this is unrealistic you haven't observed high school cheating as an adult. A chaste relationship being broken up by someone like soccer chad here, the girl has no chance. Once she makes that first mistake her brain is just shorted out on oxytocin and dick, it's a crazy...