Sadly, our culture is "monogamy challenged", more marriages fail than stay together, I think sociologists call it serial monogamy. Some people learn to be good to their partner after several failures. Sad for the kids, too.

I think it's best the way you did. I lived with my first wife 5 years, then we were married 7 years before she found someone new. Ann and I have been married 18 years now, but scars from our first marriages are still there. You might get C & R a copy of "Don't Sweat The Small Stuff In Love" or other self-counselling books. Best they don't marry now, it sure won't cure their problems!