How can i get 2 of my best girls to open their eyes?

2 of my best girls are with guys that treat them like ****.one of my girls just got dumped recently but she wants him back.he dumped because of stupid **** she did long ago.like taking pics of her tata's and showing them to another guy.this guy(her ex)have been on breaks with my girl 3 times in the years they've been together.i try telling her that he's not worth being with if he cant let the past be the past.everyone makes mistakes.and he sees her when he wants to not when she wants to and i cant seem to get her to open her eyes that he's wrong for her.and no im not jealous far from it.my other girl has been with her guy 2 and a half yrs and he shows her all the signs that he's cheating but cuz she doesnt have proof she wont leave him.i said what kind of proof do u need?std's or aids before u will believe him?he has a fit if she looks at his text msg's and he talks to this girl who works beside his work,but they arent friends or anything.even thought this girl gave him a bday card.and he doesnt care that he's hurting his gf she needs to suck it up is what he thinks.what can i do to get these girls to open their eyes and see what these guys really are??