Beating the Coolidge effect doesn’t mean that the only solution is to sleep with other people.
When a male ape believes that his mate has had sex with another male, he’ll have an even more intense orgasm with a greater volume of ejaculate in an attempt to flush out the competitor’s sperm and replace it with his own.
Of course, open relationships and polyamory aren’t for everyone, nor are they inherently any better or worse than traditional monogamy.
Other options might include taking a girls (or guy’s) night out to go party and flirt with strangers, a trip to a strip club or even social dancing where switching partners is expected (such as in swing dancing) can get you charged up…
before you head home with your honey and tear each other’s clothes off.
Humans are very bad at actually understanding the source of our emotions, a tendency known as misattribution of arousal.