Lynne1 says:
I have just read that it is in a man to have to find as many partners as possible to be able to produce as many off spring as he can, and that a woman has to find the strongest and best to have children with - how does this fit in to the monogamous marriage?

Rabbi_Boteach says:
Monogamy may not be natural, but then it is the best way to live, and caters to our emotional need to find a soul mate. Not everything that is natural is good. It is natural to be lazy. But G-d's intention is for people to be monogamous, that's why he created Adam and Eve. All experiments for open marriage throughout the generations, to accommodate sexual urges for strangers without disrupting the couple's intimacy, have failed. A good case in point is the life of Bertrand Russel.