You married because of an arranged marriage with Dazai, actually he pretended not to care about you and didn't like you even though he cared and liked you but you didnt know if he tsundere for you

When he came home at night you cooked for him because you had given your heart to him even though he didn't like you

"Sorry I already ate out when I came home from work"

then he goes to his room you just sigh