Children, marriage and divorce

Again from the New York Magazine:

... couples probably pay the dearest price of all. Healthy relationships definitely make people happier. But children adversely affect relationships. As Thomas Bradbury, a father of two and professor of psychology at UCLA, likes to say: “Being in a good relationship is a risk factor for becoming a parent.” He directs me to one of the more inspired studies in the field, by psychologists Lauren Papp and E. Mark Cummings. They asked 100 long-married couples to spend two weeks meticulously documenting their disagreements. Nearly 40 percent of them were about their kids.

If wanting children causes marriage, does having children cause divorce?