I'm assuming by the quotation mark you know that he is no way sorry. You just have to be smart and do things she thinks is sweet(but not out of hand)and that he hates. Then the ball is in his court again.
Anyways, I was once in a similar situation. I was dating this girl (in highschool pff) and her foster brother and her once had some sort of relationship. So anyways when we started dating he got exremely jealous. He thought he was in looove w/ her. W/e. So anyways, whenever I went over there he would try and start shit. But being that I was bigger and smarter, he wouldn't really do anything besides give me looks and talk shit. So I left him think hes special. He was abusive w/ her though. And that wouldn't stand, so I embarrsed him one day when 3 of his friends were over. Knocked his ass to the ground, made him say sorry to her, and that he would leaver her alone. Well anyways, she was a great lay, until I found a sleeping tshirt of hers and a pair of panties covered in white semen like streaks. At that point I figured that her and her foster brother still had some sick relationship, either that or he forced her to. And that was that.

Or paint your penis into one of those things in gravs avatar and sticking it slowly in her while making her scream out whatever you painted it into.