brother in law didnt even do anything wrong if we're being honest

I mean he was literally the cause of why the brother and the sister’s relationship broke. And he literally cheated on the guy just to make him feel bad, while also hurting a woman ( who’s the sister of his boyfriend ). At the end, he kinda did a favour to his boyfriend since his sister is homophobic and would have reacted badly to their relationship, but what he did was still very wrong