The general theory of love
Assumptions: 1. All people are of the same quality. 2. All people are constrainted maximizers. 3. One can only stay with an opposite sex at a time.
In this passage I would like to make a hypothesis to explain and predict how long a person will stay with his/her mate. It may be wrong, but it is interesting.
When one stays with his/her mate, he/she forgoes the chance to stay with another opposite sex. If he/she expects he/she can find a better mate, he/she will leave his/her existing mate and go into "market". But he/she bears a risk that his/her expectation may be wrong - there may not be a better opposite sex available to him/her in "market".
The higher the risk that his/her expectation may be wrong, the more reluctant to leave his/her existing mate one is. The lower the risk, the lesser reluctant to leave his/her existing mate is. In other words, given a lower risk one will not stay with his/her existing mate long.
You may argue that my hypothesis cannot exactly tell us how long one will stay with his/her mate. But this doesn't mean my hypothesis is useless. My hypothesis can tell us under what particular cases one will stay with his/her existing mate longer or shorter.
In a society with more females than males, based on my hypothesis we can expect that the male will stay with their mates shorter than the males in another society where males are more than females.
On the other hand we can predict that in a society with an increasing number of males the females will stay with her males shorter and shorter. There are lots more implications.
I have not yet tested my hypothesis. It may be wrong but it is quite interesting.