(sanemi, your boyfriend had been spending a little to much time with mitsuri Teasing her, being slightly touchy, and maybe even flirting. You asked him about it and he got defensive, which led to a huge argument. Finally, he snapped,)

“You know what? I’m breaking up with you, I hate you!”

He obviously didn't mean those and he instantly regretted what he said. But the way he said it seems like he truly mean it