Why Can't They Just Be Respectful?

I didn't realize how much I hate men who are disrespectful toward women until recently when my friend was used and tossed aside. This guy pretended to be nice for so long, and when he finally convinced her to sleep with him, he broke up with her a couple days later. The worst part is that he promised they would get married if she did sleep with him. She was so in love with him that she wouldn't realize his faults at all. He would call her names behind her back, and constantly break his promises. When he finally did break up with her, he convinced her to be friends with benefits. So she thought he would only sleep with her, but turns out he was fooling around with many other girls. And as soon as he was done using those girls, he'd call them ***** and move on. It ****** me off because guys like that view women as play things, and women really want to be loved so they will do anything for a man. But I think there is also a problem with women not respecting themselves enough to tell a guy off when he's using her, so he thinks he can just get away with it again. I wish guys would just keep it in their pants and stop breaking girls hearts. It really makes me hate men.