Twenty-percent of couples have experimented with consensual non monogamy [but] open marriage has a 92% failure rate.

What percent of couples have open marriages?

Research tells us that about 4 to 5 percent of heterosexual couples have agreed to have an open relationship. In other words, theyve given their consent to not be monogamous. That may seem like a relatively small and, given the stigma surrounding open relationships, unsurprising number.