Chad said: For a half second I was very intrigued by "the Rule of Three" for relationships.
Of course there is an obvious way to apply the rule if you are an aspirational polygamist but that would likely prove to be very expensive in the modern market. I am more scared-straight than cynical on the topic of til-death-do-you-part-sexual-contract. In the last year, I have been weekend house-guest with 5 different middle-aged couples who have sex-dead marriages in which they are stranded or locked due to sunk-cost-fallacy. Usually it is the wife who calls it quits on sex (4 of the couples I visited) , sometimes it is mutual and both parties are content with the situation (1 of the couples I visited) but more often than you might think it is the husband who shuts down shop (my own first marriage.) Therefore, I often have empathy for the husband's situation. I even have empathy for my current SO's fears that he may put himself in financial risk if he legally marries me even though this requires me to imagine a future version of myself who has fallen madly in love and under the dark, dominant spell of a highly skilled divorce attorney.
Anyways, I do now know the Rule of 3 Practices for insuring steady supply of high quality sex. Long term legal contract is neither necessary nor sufficient.