Let people make their mistakes. Fact is you don't have visibility into what happens when they're in private. They might be dynamite together. You don't know. Now I'll admit, I find the "if it looks like a duck..." Rule is almost 100% true. That all being said, in the dozens of people I've helped in relationships, I've never, not once, not ever heard a woman tell a guy she was dating, "you were right about that jerk. I really am better with you." It's never happened. And I doubt it ever will. I have heard women say "I was right about that jerk. I'm better off with you" but it's the "I" that's important. It needs to be their realization. Their decision. You can't have anything to do with it.