More people want open relationships, but many don't last. A sex researcher shares the 3 top reasons couples return to monogamy.

Non-monogamy comes with its own challenges, Dr. Justin R. Garcia, the executive director of the Kinsey Institute, told Business Insider.

Hinterhaus Productions/Getty Images

• Dr. Justin R. Garcia, head of the Kinsey Institute, said non-monogamy has gotten more popular.
• However, he said open relationships and polyamory tend not to work for most people.
• Some find non-monogamy to be too much work in practice.

Open relationships have gotten a cultural glow-up among younger adults.