A couple who had to make the difficult decision to tell doctors to halt CPR on their newborn child are opening up about watching their "worst nightmare play out."

"It hasn't been easy being a mom and dealing with grief ... I struggle with the question of 'How many kids do you have?' " Morgan Christofferson tells PEOPLE

Morgan Christofferson, 25, shared the worst moment of her life - the time she and her husband had to tell EMTs to stop CPR on their one-year-old son.

A husband and wife team from Minnesota have opened up about the fateful decision they had to make about their 14-month-old son diagnosed with a heart condition, and how they've coped with it since