What would you do?

So I have this friend that I’ve known for years. I’ve met her boyfriend, know her family, watched her baby grow up.

Well, she’s been dating this guy for about 5 years now and he’s a great guy. He’s paying for her to go through college, takes care of her kid like it’s his own, expresses how much he loves and cares for her all the time.

But she’s been cheating on him with multiple different guys. And I know this for a fact because she’s told me and showed me the messages. But I feel really bad for her boyfriend and think he should know about this. But I definitely don’t want to be the one to tell him because I don’t want to jeopardize mine and her friendship. I have told her multiple times that I think it’s wrong for her to do that but she doesn’t seem to care. She said she loves her bf but is bored of him because they’ve been together so long. And she said she won’t leave him right now until she’s done with school and gets a job to support herself. I’m just torn every time she tell me about one of her newest hookups while her boyfriend is clueless.

What would you do if you were in my shoes? I want to mind my own business but I’ve been cheated on and know how bad it hurts. And at the same time I don’t want to loose mine and her friendship.