"I posted that from the bottom of my heart to my husband, because I know that I don't give him enough recognition for how phenomenal he is as a husband and a father," Sara Duncan told "Good Morning America." "I could tell him, but it's not enough. I really did want to tell people, 'It's not always going to be perfect, but it will always be worth it.'"
Joe Duncan works as a cement technician and had just finished a 12-hour shift that night on March 23.
Sara Duncan said she told him she wanted to bring their daughter to the hospital to be evaluated after noticing she was wheezing.
Sara Duncan said Joe Duncan had to return to a morning shift a few hours later, so he changed into clean work clothes and took the one-hour drive with his family to the hospital.
"He's a 'I have to be with you' type of guy," Sara Duncan said. "I knew that he was exhausted. I said, 'Stay home. I know my way at [the hospital], and he was like, 'No. You're not going up there by yourself.'"
Sara Duncan said her child received minor treatment and was cleared to go home after two hours.
When Sara Duncan looked down on the ground, she said, she noticed Joe Duncan using the car seat as a pillow to sneak in a snooze.
"I was looking at him thinking how thankful I am for him and how I wouldn't want to do this life without him," Sara Duncan said as to why she wanted to capture the moment.
"Parenting is really hard," she added. "I can't imagine doing it without him. Kudos to single moms. I have a husband who cooks, cleans, does diapers and baths, and I'm still exhausted."
Sara Duncan's post was shared more than 31,000 times. She wrote:
"Let’s talk about this because it doesn’t get enough attention... What some may see: Dad sleeping while Mom stays awake holding their sleeping baby in the ER at 2 a.m. What I see: Dad sleeping on the hard floor of an ER after working 12 hour shifts 6 days a week for the last month, despite the fact his wife asked him to stay home and rest, all because he didn’t want his babies in STL alone. Because he didn’t want his wife to have to do it on her own, no matter how exhausted he is."
"Marriage and parenting isn’t 50/50. Some days it is. Other days it’s 60/40, 70/30, or even 80/20. And you have to be willing to pull your weight, no matter what your partner needs that day. This is what love is. This is what being a husband is. This is what being a daddy is. And I wouldn’t want to do this life with anyone else! Thank you for all you do for us Daddy! We love you!"
"Look for that in your partner and appreciate that 60/40, 70/30," Sara Duncan told "GMA." "Everyone deserves that."
The image was also shared by website Love What Matters, which then ignited conversations surrounding the importance of couples equally sharing the parenting load.
Reproductive psychiatrist Dr. Alexandra Sacks told "GMA" that while society has come a long way when it comes to acknowledging men and women equally, whether it be at work or inside the home, the equality issue is far from resolved.
"In my patients I often see that mothers and their partners value shared parenting roles and responsibilities, but often in the day-to-day domestic tasks and the work of what we call "emotional labor" -- the invisible labor of caretaking -- still disproportionately falls on the women," Sacks explained.
"It's important that we keep talking about this in the workplace and on the domestic front if we're going to keep moving forward in our culture and if parents and all people are to be valued equally," she added.
Sacks said it's important to discuss your expectations of roles and responsibilities before entering parenthood and to touch base over time about how the division of labor is working out in your relationship as your parenting experience evolves, she added.