It's his fault for staying with her after the stabbing and trusting the crazy broad. And not to be a jerk about it, but it's probably his fault she hooked up with some other guy cause he wouldn't tap dat. Any sexually mature/active person is going to look for theirs 1 way or the other. I understand he was young and naive and i'm sure he learned a lot, but he learned the hardest way.
As for hit me, i hit you. An eye for an eye makes the world go blind, my friend. And in most cases courts are going to side with the woman in a domestic abuse case. So if you don't want to go to jail, charged with abuse against women, I'd reccomend finding alternatives to 'beating a woman's ass'.
He did mess up, by going back with her, so getting cheated on is his fault. And he wasn't tapping because he was an evangelical Christian, hardcore, and she knew that when she met him. In fact, they would go to church together, every week. They'd invite me, and I wouldn't go. If she wasn't into it, she should have been upfront. Either way, there's no reason to stab anyone, and that's not his fault, no matter what you say.
As for going blind, or whatever, I don't go with pop-culture sayings. I heard that saying, on some TV show, where they were talking about war, something which arbitrarily kills people and that I'm against. Now, I live by a code of ethics, which includes mutual respect: I will always respect a person, as long as they respect me, and I don't expect respect, if I fail to give it. In the course of my work, for the NYPD and the NYC public school system, I know that what you're saying is the result of lack of knowledge and experience. Straight up, I'll whip a kid's ass, a man's, a woman's, anyone who tries to do me, or my loved ones, evil. I've seen evil, from rapists, molesters, child abusers, people who enjoy humiliating and torturing others, in kids, women, and men. They understand one thing: punishment and fear. If an evil person thinks that they can do what they want, and nothing will happen, they'll do it with a smile.
I've seen women molest little girls, boys rape both females and males, teachers rape people of both sexes, uncles molest nieces, especially when they're foreign, little kids disfigured, physically, by starvation or by burns and cuts, resulting from physical abuse. These people are never remorseful, never in search of redemption, and you wish you could punish them, but you can't. Now, if someone tries that type of stuff on me, they're going to catch hell. I know what's out there, I still suffer from nightmares, as the result of some of my work. Most people, when tested, as to the their moral courage, fail, I know this from experience.
The world is screwed up for a reason, kid, and it's not because half of the world is composed of lovely people, of the female sex, who simply cannot influence the other half, who deserve all of the beatings. Be a little more critical of what you hear.