Picture this: There's a couple. Two people who have been dating for a while, who post aesthetic posed pictures, who surprise each other with little gifts that they then show off on their social media, who wear each other's initials at all times. Then, the guy cheats.
What would you expect?
They break up. He gets a bad reputation. The girls in school trash talk him, the guys talk about how stupid he was. He pays for his mistake for a few weeks, then people mature and get over it, and everyone moves on with their lives.
Wrong.
Instead, the girl he cheated with is blamed. She gets a bad reputation. The girls in school trash talk her, the guys talk about how easy she is. She pays for her actions for months afterward, and she was not even the one in a relationship.
So girls:
It is time to stop slut shaming other girls. If your boyfriend cheats on you with another girl, you have every right to be mad. In fact, you should be mad. But be mad at him, because he was the one with the obligation to you. He was the one who promised you he would stay loyal, who whispered sweet nothings into your ear, who held your hand and met your family and made you trust him. The girl had no duty to tell you, she may not have even known he was in a relationship. And even if she did? It may have been somewhat unethical on her part, but she is single, she is uncommitted, she can do what she wants. You don't have to like her or be friends with her, but she is not the scapegoat in the situation.
Him on the other hand? He is not. He deserves the blame, he deserves the anger, he deserves the twitter drama. Stop blaming and shaming the girl that your boyfriend lies to you about, start making him take responsibility for his actions. Show him that disloyalty will not be excused and it will not be pitied.
He made a conscious decision despite the fact that he knew he had an obligation to you. That's on him. Not on anybody else.