Glad that this is back!
Nine needs to learn to manage his anxiety and his codependancy.
Like, it makes sense that he's overprotective, she almost died back then, she's his reason for living, so obviously, he wants to cover her in bubble wrap and make sure nothing bad happens to her again.
That being said, you can't stop someone from being themselves.
He wants her to be "safe" according to his standards, but Melissa doesn't share those standards, hence she's getting pissed off.
Nine is being pretty toxic right now, even if I can understand where he's coming from, he won't get what he wants if he stays this way.
Aka, Nine will have some character development 😁