Human history is, in a certain sense, the history of millions of couples through the centuries. In the past time the specific role for a woman and for a man, in the context of a couple, seemed rather dissociated: they could not be both mother, father, lover, children's teacher, friend, but had to choose a predominating role. On the contrary nowadays the couple is under social and cultural pressure forcing them to acquire a multiple capacity of playing different roles simultaneously. That could explain the increasing of difficulties, especially for a lasting agreement.