I dont want him to be the bad guy but y'know... Yes he didn't cheat or anything. The only bad thing doc does was hiding his social life from uke. But that itself is already kinda a big taboo in a relationship. ( ̄∇ ̄")
Tbh i had been in the doc's position. I didn't cheat or anything but I was pretty social back in college and this guy thought I was a pure innocent girl next door. It was a disaster for me because I felt like i was gonna get busted all the time and ended up cutting it off before i get busted lol. That could be because I wasnt actually serious about that relationship (unlike the doc, i dont think he's gonna cut uke off since he's serious), but the fear was real; both sides. The person hiding and the person hidden from.

So the doctor ain’t a cheater and he didn’t really make a “date” appointment with the other dude. He actually really love the uke but something happened in the past that is holding him back. That is the reason why he seems suspicious. And if y’all still want a spoiler would gladly do so, just like the comment. ╮( ̄▽ ̄)╭