Maks Chmerkovskiy 'Completely Lost It' Right Before 'Raw, Unapologetic' Dance with Vanessa Lachey

This week’s Dancing with the Stars was an emotional one across the board.

On Monday, pro Maks Chmerkovskiy put on his dancing shoes to compete with partner Vanessa Lachey in a routine commemorating her most memorable year — one week after missing last week’s show after sources told PEOPLE the two had hit a rough patch.

Lachey, 36, chose 2017 as the most impactful year of her life, breaking down in tears as she revealed that she underwent an emergency surgery when her son, Phoenix Robert, arrived 10 weeks early in December. (His due date was sometime in spring 2017.)

Lachey and Chmerkovskiy, 37, earned a 24 out of 30 for their emotional rumba, and the dance pro later took to Instagram to pen a sweet note to his partner.

“I’m proud of you partner!” he continued. “They can say what they want but you’re a star and I wouldn’t want to be on this rollercoaster with anyone but you! And we have so many more of these moments to share with each other, and everyone else who couldn’t stop their tears… #teamBabiesAndBallroom #DWTS #NeverADullMoment.”

Last week, DWTS co-host Erin Andrews informed viewers that Chmerkovskiy’s absence was due to “a personal issue,” but sources told PEOPLE that the DWTS pro, 37, and Lachey, 36, had been “bickering” since the beginning of the competition, and that he chose to sit out from rehearsals and the live show due to a clash between their “big personalities.”

Chmerkovskiy later apologized to Lachey for his absence, which left his partner to perform with first-time pro Alan Bersten.

“As you are all aware, I had to leave the show last week to take care of some personal issues. I take full responsibility for my absence,” he tweeted. “And want to apologize to my partner Vanessa. We are both looking forward to dancing for our fans next week!”

PEOPLE’s special issue, 25 Seasons of Dancing with the Stars, is on stands now.

Chmerkovskiy’s wife — and fellow DWTS pro — Peta Murgatroyd shared with PEOPLE that even though “a lot was made of the fact that Maks missed last week’s show,” only a “few people know how crazy this show really gets — not only physically on your body but mentally as well.”

“We care about our partners, and that’s what makes it so hard sometime, because you care and love each other, and you want them to do so well,” she said. “You invest so much time-wise, and you just want them to be the best and get the best results possible at the end of the day on the Monday night. But it is difficult to deal with life, stresses, rehearsals and then show time and everything that goes along with that.”

Dancing with the Stars airs Mondays (8 p.m. ET) on ABC.