Marriage is still a solid institution but in need of reforms!

So many social scientists tend to consider marriage in its traditional frame has now become 'dead wood' and a better alternative may be 'Mensge a Trois'. There is some truth in this given the increasing rate of divorces. Other signs of a married life failure would be wife cheating on husbands or husbands cheating on wives, a social phenomenon on the increase, too. My idea is to sustain marriage as the corner stone of a civilized society but bring about a few changes in the attitudes of marriage partners. For example, a husband who performs poorly in bed should allow his wife to take a lover and exclude himself totally from her new extramarital sexual relationship. The same with a wife unable to satisfy her husband sexually. She would consent that her husband has a mistress or a bit on the side without trying to join in or disrupt their intimacy. So, a reformed marriage could be Menage a Deux plus a lover to help if need arises.