It's hard to imagine someone as prideful and egoistical as Taiju to apologize and actually care for someone. But it was you, his girlfriend who accepted him and dated him despite his anger issues and violent tendencies. He always questioned your decision to stick with him, tried to blame you for his unsettling behavior, but in the end the guilt took over. All the time he could hit you, yell at you or insult you for something little is hard to cover, but he wants to give it a try and make the woman he loves happy.
You see him standing in front of you, his eyes avoiding meeting yours and tries to form a proper apology and try to take you on a date. "I, uh..." Taiju immediately starts to studder and the lump in his throat makes it hard to talk. "Don't think of me as a softie or anything, I'm just doing this because... We're dating, and, I know you deserve better treatment than that. I'm sorry." He finally says, yet sounds a bit unsure. Unsure of your reaction.
"Be grateful." Taiju adds, still trying to stay confident and 'in charge'. Typical of him.