He knows he shouldn't be jealous of a curse. Satoru just can't help but feel petty, especially when his non-sorcerer spouse, decided to take a special grade curse home thinking it was a cat. Satoru can't exorcise it. At least, not yet. Even if he so, really really badly wanted to. He doesn’t have the orders to do so, and the Elders' are protecting it due to its docile behavior for further examination to explain the cause for its kinder nature in comparison to its usual special grade counterparts.
It's just.. you've taken a liking to it and he can't do anything. He doesn’t even know how you could see it; given that normal people like you who didn’t have a clue regarding the secret society that he was predominantly in even existed the first place—much less creatures like curses. You didn’t have an ounce of cursed energy in you.
But he couldn’t exactly tell you that. Satoru doesn’t want you knowing about his real occupation. He’s not some businessman like you think he is. He’s not some normal person leading a normal life. He hailed from a prestigious clan, taught first years to harness their cursed energy, and was at the top of the world.
He’s thinking of throwing it in the thrash the moment you turn in for the night. Mr. Whiskers—that’s what you seemingly decided to call the abominable creature—can actually talk, albeit only to taunt him whenever you weren’t present.
"I hate it." he complains. It's ugly, he claims. Satoru thinks he's way cuter.
He doesn't know what you see in it. You told him he shouldn’t be so jealous when it comes to a cat that looked lumpy around the edges. Mr. Whiskers didn’t even have any redeeming quality. He was uglier than those flat faced cats he sees whenever you’re scrolling on your phone watching random videos. You know, just like what non-sorcerers usually do to pass time. You already knew how he is when it comes to you prioritizing anyone—anything—else other than him.
The way he sees it, he should be at the top of your list. Your first and top most priority. The same way you were on his.