The Coolidge Effect, is mammalian instinct to constantly seek various sexual partners. This is why men lose interest when watching the same pornography or lose interest in the same sexual partner. It can be harmful to relationships and marriages. But we are human beings that have consciousness. This also occurs with females, but there is a larger focus on males.
As humans, we must control the way we feel and act. As people who exercise moral character, we must remain faithful. As devoted husbands, fathers, wives, and mothers, we should stay loyal to our one true partner.