A British couple, seven years married, set themselves a challenge of daily sex for a month. They were returning to the practice of their first years of marriage, which they had drifted away from. However, they found that the daily sex experiment was harder to stick to than they thought it would be - normal life raised many hurdles. Still, they also found that it brought them closer together, made them more attentive to one another, and they looked and felt better.
What struck me about this experiment was that they found it so challenging without children. One weekend they babysat their small nieces, who wished to stay up and be entertained. When she fussed to her sister that the kids would cramp their challenge, the mother of the small girls simply said "welcome to my world."
The Kavanaghs ended the account of their experiment in the Daily Mail by saying they were glad they did it, never felt closer, and wanted to start a family.