ZoLaw in which Zoro has an immediate interest in Law, an odd mesh of feelings toward him that's so tangled up he isn't sure what it is, so he pushes it aside. The more they spend time together, the more Law seeks out his company when the others get too rowdy, the more quiet moments they share where it feels like they are the only two people in the world, the more Zoro realizes that those complicated "thoughts" he was having about Law are, in fact, feelings. Emotions. He is emotional about Law.
At first he is confused as fuck, but he sits on it and decides "yes, I DO like this guy" and that's when his protectiveness kicks in. Knowing Law’s past and his beef with Mingo makes him SUPER protective. He won't let Law out of his sights, he HAS to be near him, he has to know what he's doing. If Dressrosa was anything to go by, Law CLEARLY doesn't know how to take care of himself...but that's alright because Zoro is there to make sure he doesn’t do anything stupid.
Now Law can't step foot on an island without Zoro there, can't talk to strangers, can't clean his sword, can't go ANYWHERE by himself because Zoro "knows better". He is smothering Law and it's so fucking confusing for Law because he liked Zoro, appreciated his desire to protect his friends, but THIS was a bit much and Law isn't sure he can last under this attention.
Of course, Law pushes back, not liking to be ordered around, even if it was Zoro, but Zoro said it was because he cares. He said it so blatantly the one time it all came to a head. It didn't help that the Straw Hats backed Zoro’s behavior, not seeing just HOW obsessive this man is being...all they see is their gruff friend warming up to a new person. And if ZORO likes Law, that's an official stamp of approval for the rest to bring Law into the fold.
This forces Law to suffer beneath the weight of Zoro’s obsessive, near possessive, attention. The only light is the approaching end of the alliance.