Polygamy!! I hated this part in TF. So much selfishness and hurt and humiliation.
Selfishness: for one partner to "use" the letters for his own benefit and fun and prove he/she is better, and leave the "old" one by himself
Hurt: not to be respected as a person, a human being with a life and the right of his privacy and family
Humiliation: often the second "wife/husband" did well to treat you in a way so you would know your place: bottom
And then the KIDS: The circle of a family had an intruder that sometimes was okay, sometimes their kids got preferred in order to show "love". Plus they saw and felt that a world is breaking down because of "love and trust"
My ex had mentioned that the last years of our being together he had build himself almost his own sect, like Berg.
I actually do believe that it is almost impossible for a man to stay monogam. For some woman too, but I think we can draw the line easier when it comes to find out when enough is enough. or?