Most sexually active adults know routine sexually transmitted infection (STI) tests are an essential part of sexual health, but once people enter a monogamous relationship, they often stop getting tested.

This is one of the biggest mistakes you can make for your sexual health, as many STIs can be slow to spread or might have been missed in an earlier screening.

"Making testing a part of your routine care ensures you're capturing infections that might not have been detected during prior testing," recommended Jenelle Pierce, executive director of The STI project. "If you get tested too early after possible exposure to an STI, the infection might not be detectable."

Some people don't show symptoms

"If your partner doesn't have symptoms, it doesn't mean you or your partner are not infected," said Anne Rompalo, M.D., a board member and medical consultant for the American Sexually Transmitted Disease Association.

This is one of the most common misconceptions she has encountered in her time diagnosing and treating sexually