Carolyn Hax: New girlfriend isn’t as affectionate as the ex. Was breaking up a mistake?

Dear Carolyn: I’m dating the most wonderful guy. I am 25 and have dated several guys over the years but never one like this. If everyone treated each other the way he treats me (and, I think, I treat him), the world would be a happy place. And, it’s not just that he treats me well, but we enjoy the same interests and share similar values and morals. Since the beginning I’ve been having one of those, “Ah, so this is what it’s supposed to be like,” moments. But, after all this gushing, I see these unhappy married couples and I think, they must’ve had the same thoughts I did. What is it that goes wrong?