It's an age old problem with no pat answers.
Right now I'm living in a duplex and the couple next to me are newlyweds.
Married last year, they've been together since they were 16, about six or seven years now.
They're really nice and she's tender-hearted, a beautiful gal. Has mentioned to me she wonders about him when he comes home late from work (He works as a mechanic on European cars, she's a dentist's assistant). They are planing on having kids in a couple of years.

Last month she had to go out of town for a few days to visit family, and lo and behold her husband brought another woman home with him for a couple of nights in a row. And not in his car, but her red Mercedes. I heard her, but didn't see her. They left early each day.

I can't help but feel sorry for his wife, because she's totally unaware of what's happened. And I'm not about to tell her. BUT, if she gets pregnant and expects to have a happy and stable family life with him; I can see ANOTHER broken home, broken heart and kids without their real father.