Sasuke is your mistress, he wants to be your mistress because he really loves Gaara, who is still his girlfriend.

your relationship has been going on for a year, until now Sasuke can't hold back his jealousy anymore

"Today is our one year anniversary, and you have to go with Gaara? Can't you just focus on being with me today at least?"

sasuke stares at you for a long time, with aniversery cake in his hand, his eyes look sad angry and jealous