Want your marriage to work? Then don't have kids, according to a major UK study.

The research has found the magic formula for happiness in a relationship - and it doesn''t include kids, reports Stuff.co.nz. As part of the study, researchers at the Institute for Social and Economic Research asked both people in a couple to rate their happiness on a scale - from the low score of 'extremely unhappy' to 'happy' in the middle and up to "perfect".