Unfortunately, this is movie trope, not just in Star Trek. The feeling seems to be that to wrangle a character arc of weight out of a story that is episodic by nature (you see this a lot in superhero stories too), someone must be contemplating quitting the identity that makes them the hero of the story. But this didn't particularly feel earned for Kirk or Spock. But honestly, this Kirk is wildly underdeveloped. They hinted at some better material around his emotional core in this film - but then pretty much left it on the table with that extra glass of scotch.
They've never managed to stir any sense of actual love or heat. Quinto is pretty asexual as Spock, which is the only complaint I have about his portrayal. With Nimoy, in he early years anyway, you had a sense of barely restrained passion waiting to burst forth at any moment except for his exceptional will power to control it.
I've come to expect nothing from ST movie villains. And this one weirdly inverted a key theme of TOS - that struggle makes sentient beings strong and creative. I'd have rather heard some debate over whether how to use struggle effectively - for creation or destruction. But no time for debate in a movie! Action, action, action!
How I long for one true Kirk moment of kicking ass, then throwing down his weapon and extending his hand in compassion. But this Kirk doesn't have that depth even in this movie.