Chris broke his leg during training in 2013.

While planning their 2016 wedding, Alexa was diagnosed with a rare gastrointestinal condition that left her fighting for her life.

Jeff Knierim, Chris' beloved father, died at age 49 in July 2017.

They moved three times and had two coaching changes after the 2018 Olympics.

Chris asked Alexa Scimeca to marry him in 2014.

Scimeca-Knierim won their first U.S. title in 2015.

They married on a sunny Colorado day in 2016.

Knierim-Knierim won the 2018 U.S. title and a spot on the U.S. Olympic Team.

In the Knierims' love story, this is merely another chapter, hardly an end.That's how three-time U.S. championssee it, as together they announced that Chris is stepping away from competitive pairs skating while Alexa will seek a new partner with eyes on the 2022 Olympic Winter Games."I'm getting older," Chris, 32, said Monday sitting beside his wife, Alexa, in their Irvine, California, home. "I've been struggling with injuries – one gets better and then another pops up. I've been struggling with my jumps a lot this season and now I'm ready to move on. But Alexa, she's still gung-ho and ready to go, no doubt. She's such an athlete and competitor. I support her 100 percent."Their decision also means they will not compete at the ISU World Figure Skating Championships 2020 next month in Montreal. The Knierims will be replaced by training mates, the U.S. World Team first alternates."When Chris and I made this decision, there was no anger, no fighting," Alexa, 28, said. "We love each other so much that we want to see the other person be happy. Our marriage is stronger than ever."Through their eight seasons together, the Knierims have weathered major challenges and loss.But the joy and exhilaration have been there as well."If you look at it," Alexa said, "there's something monumental in our lives every two years: 2012 we formed as a team; 2014 we got engaged; 2016 we were married; 2018 Olympic bronze medal; and now, 2020, Chris is stepping down. It's an interesting timeline that makes me wonder what will happen in 2022."Chris said he knew his athletic career was winding down in December, when he began to lose his passion for the sport. He had bouts of depression and said their coaches, Jenni Meno and Todd Sand, saw it, too."It became evident to me and our team that I really needed a break and that I was burned out in general," Chris said. "I had hard days when I left practice early and then we went back and forth about even going to nationals [in January]. The week before the competition, I said to Alexa, 'should we go?'"Alexa felt her husband's struggles and offered her full support."First and foremost, I'm his wife over being his [skating] partner," she said. "We know skating ends and life continues. For us, our marriage, our relationship is what's important."I wanted to make it clear from the beginning that he could make our decision and that I trusted him with that decision. We told our families not to make any more plans to go to nationals quite yet. Even on the day before our flight to Greensboro, I told Chris again that he could still make that decision [not to compete]."But Chris pushed on."I'm not a selfish person, so it was hard to make a decision that affects Alexa so much," Chris said. "I had the confidence that we could skate well, and the year before -- when we finished seventh -- was so disappointing. I wanted to make sure we ended this season on a positive note."Their final U.S. Championships ended with an elated Alexa jumping up and down in the kiss and cry while a smiling Chris sat rubbing the spot on his chest where his wife thumped him in jubilation.But even with that third U.S. title in their hands, Chris was unhappy as he tried to cope with what had become a daily challenge just to get on the ice."To see the change in him, sorting everything out, was hard," Alexa said.Chris' battle with depression came to a head in February at the ISU Four Continents Championships, a competition they had medaled at in 2014 and 2016."Four Continents was really strange," Alexa said. "In our three practices in Seoul, Chris was physically there but he wasn't present. It was like I was skating with a ghost."When I took my spot in the short [program], I looked at his eyes and he wasn't there. It was like skating with a body, not my husband."After errors on their side-by-side jumps, Chris fell on the entry to their side-by-side spin and could do nothing but stand next to his spinning partner."I'm done," Chris told Alexa even before leaving the ice."I knew this was not just a reaction to our skate," Alexa said. "He was done. I knew that mentally and emotionally."They withdrew from the free skate. But kismet has a funny way of presenting itself: Etta James' romantic "At Last," sung by Beyoncé, is the last program they would compete together.Once back home in California, Chris told Alexa his decision was final."Undeniably proud. Those were the exact words that came out of my mouth when he made the decision," Alexa said. "I am truly proud of him."Chris, who is receiving treatment for his depression, isn't sitting back, as he will be part of Alexa's coaching team. He also will continue coaching younger pair athletes with Meno and Sand and plans to get back to doing what he loves: working on cars.But right now, he's looking forward to his wife's skating future."In so many ways, my wife supports me," Chris said. "We have a special bond and being able to have skated with her has been huge. Through all the struggles I've had, Alexa has been a rock and I respect her so much."I look forward to watching her keep skating and will support her in every way I can. Alexa is very tenacious and strong. She's fire on the ice. Nothing can stop her."