Pré-publication, Document de travail: We here ask whether the U-shaped relationship between life satisfaction and age is flatter for those who are partnered. This is the case in cross-section EU-SILC data, where the drop in life satisfaction from the teens to the 50s is almost four times larger for the non-partnered than for the partnered, whose life satisfaction essentially follows a slight downward trajectory with age. However, the same analysis in three panel datasets (BHPS, SOEP and HILDA) reveals a U-shape for both marital groups, although still somewhat flatter for the partnered than for the non-partnered. We suggest that the difference between the cross-section and panel results reflects compositional effects: there is in particular a significant shift of the relatively dissatisfied out of marriage in mid-life. These composition effects will flatten the U-shape in age for the partnered in cross-section data.