Zeke is not telepathic. Nobody is. If MC refused to ever truly talk about Kayla, that's on him, not Zeke. You'd be surprised at the kind of things that so-called 'best friends' choose to keep from each other.You have to be real here - what kind of a friend is Zeke if their so called best firend relationship
never includes what kills MC inside, neither tha fact that MC has BEEN totally FALLEN FOR kEYLA HIS ENTIRE LIFE,
...
Kayla broke things off multiple times, but then got back together multiple times too - hence my emphasis on 'not permanently'. It's not like Z forced her into it, or blackmailed her (at least as far as we know). She chose to be weak and indecisive, she chose (just like the MC) not to come clean to Z about who she really likes. Again, that's on her, not on Z.
During any of those 'breaks' that happened, Kayla could have talked to MC, and the two could have made it official. They didn't do so.
Do I like Z? Nope, he's an annoying idiot who injured the MC, a needy fool constantly pursuing women who aren't that interested in him, and a cheater who can't even walk away properly from a failed relationship. But he didn't 'up' anybody 'in a grand way', nor did he cuck anyone - that can all be blamed squarely on both Kayla and MC. Apparently, neither of the duffer duo heard of the old adage - play stupid games, win stupid prizes.