You are newly married and find out that a baby is on the way. What joy! What wonder! Then the baby is born and "kablooey!" The once loving relationship you had with your partner has devolved into a no-holds-barred battleground. What happened? More and more couples are quickly finding out that there’s nothing like a bouncing baby to take the bounce out of a stable and secure relationship.

Friends Cathy O’Neill, Stacie Cockrell and Julia Stone realized this as they began to compare notes with each other. When they found that they were experiencing the same kind of post-baby upheavals in their marriages, they started to survey others. They talked to strangers in supermarket checkout lines, the guys at their husbands’ poker nights, and couples across the country. After all the talking, they wrote a book, 'Babyproofing Your Marriage,' a personal, often funny look at the his and her perspectives of life B.B. and A.B. -- before baby and after baby -- complete with tips on how couples can regain the magic.

“This book started because we were looking for a book to get through this period of our marriages,” says co-author Cathy O’Neill, who recently talked to AOL Coaches from her home in Austin, Texas. Now, she says, 'Babyproofing' has become a conversation starter in marriages, helping couples to find the words to explain what they are experiencing after they become parents.

“We are not therapists,” O’Neill says. “We are not on our soapbox. This is what works for us or other parents. We are still living this book. It’s a work in progress. We are thrilled to share what we have learned.”

So what did they learn? Here are their top four life-changes after baby arrives and some tips to rekindle the spark that got the couples together in the first place.

1. Sex, or Lack of Sex. O’Neill says the reason for the sexual disconnect is that the woman’s sex drive goes missing in action after having a baby. Men, she says don’t experience the same post-pregnancy seismic shift. “There’s so much going on after the baby is born,” she says that most women, given the choice of sleep or sex, will choose sleep. Men, on the other hand, want sex as much as they ever did. O’Neill says that when wives deny their husbands night after night, men often feel rejected and start to hear their wives say, “I don’t love you anymore.”

The Fix: Have a date night, even if the date is at home after the baby is asleep. Turn off all electric gizmos and talk to each other, O’Neill says. Get off your sofa and sit beside him. And force yourself to avoid talking about the kids. The children are an important part of the relationship. But O’Neill says, “If that becomes the only way you relate, the marriage is going to wilt.”