1. Know your Z.
There's a children's book out there in the world called Chicka Chicka Boom Boom, which, like most children's books, is also for adults. In it, all the letters of the alphabet march up a palm tree, one by one. As each ascends, the tree leans over a little more, until a certain plucky Z scales the trunk, at which point the tree, and every letter on its branches, crashes to the ground—boom boom. Marriages are a little like this. There is a definite identifiable Z. The Z is not a hurricane or a bankruptcy or other tragedy that just happens to a couple. The Z is often a fun or exciting idea—that third baby or the move to Cleveland or the dream house that's just a little too expensive. Your friend and her husband, however, are piling it on top of their two full-time jobs, their two kids (one of them a very angry toddler), her aging mother, the master's degree he's pursuing at night and the crocheting business she's pursuing at dawn. "Don't add that Z!" you may think to yourself, or even say to your friend, "Humans have a limit to what they can manage without going insane and loathing every single person who demands so much as a Kleenex from them!" But it's too late—boom boom. It would be nice if you could learn from your friend's experience by saying, "My spouse and I will never fall victim to a Z." First, however, you have to know what that Z is—which means examining the rest of your life together, A to Y.
2. Try it before, not after.
I have a pal who spent six years mashing butternut squash, learning baby sign language and spending afternoons with mommy friends that bored her to the point of drinking Chardonnay at playdates (one glass). She called up everybody she knew (including me), explaining how lost and unhappy she was. She felt her life was empty, except for the kids. Which led her to realize that her marriage had to be empty, too. She left the marriage. After she left, she had to get a job at an ad agency to support herself. She felt great! She loved working—but she missed having a partner. More than a few friends (including me) thought, "Couldn't she have just gotten a job first, and then figured out if she wanted to stay with her husband?" To be clear, nobody should have to stay in a relationship where she's miserable, but before you take the big, drastic step of ending your relationship, it's worth trying to take the big, drastic step of changing your life—isn't it? At least, then you'll be able to say, "Hey, it wasn't me. It was us."
Next: What she's bound to discover