ET caught up with the former Bachelor and his pro partner, Peta Murgatroyd, at one of their rehearsals in Los Angeles, where he opened up about the low score of five he received from judge Len Goodman during Monday night's show.
"It cut me at my core," Viall, 36, told ET's Kevin Frazier on Wednesday. "It hurt. The truth is, I felt really bad, just because I think some of the feedback we got from the judges was even directed at Peta for almost, like, making the choreography too difficult. But, the truth is, it wasn't like she has amazing [difficult] choreography."
"I just kind of choked in the middle," he admitted. "Because she's doing such a great job, and [the judges] kind of put the pressure on her, and it was up to me to deliver, and so, seriously, it felt like... I feel like I let her down."
When Frazier joked that Viall just needs to find his "man groove," the Milwaukee, Wisconsin, native explained it probably won't be happening next week, as the two have to be "stiff" as they take on the tango to Lady Gaga's "Poker Face."
"It's kind of good for Nick right now," Murgatroyd teased.
While Viall is discovering ways to tone down his nerves, the 30-year-old dancer is still trying to figure out the secret to balancing motherhood with her insanely busy schedule. But she had no shame talking about what really goes on behind the scenes when you're a new mom trying to make it work.
"I'm just doing this. Running back and forth, feeding all the time, running back and pumping during rehearsals… sometimes I'm like, 'TMI, sorry,'" she said. "It gets kind of crazy. We have our allotted time for dancing, and I try to spend as much time at home to try to balance it all out."
On top of all of that, her fiancé suffered a painful calf injury in rehearsals for week two, which is keeping him from dancing with his partner, Heather Morris, and out of the competition for another week. Alan Bersten will once again temporarily fill in for Chmerkovskiy on Monday.
"Maks has been super great," Viall said. "He'll give me little notes, he gives me little pointers, like he's actually been incredible."
"I have a little bit of a crush on Maks," he added. "I think so does Vanessa. Who doesn't love Maks? But in all seriousness, he's very gracious with his time with me and he's as much as part of our team as his own."
Viall may not have a little one on his hands just yet, but he, too, has been balancing his schedule in order to spend time with his new fiancée, Vanessa Grimaldi. Ever since he proposed to her on the season 21 finale of The Bachelor, rumors about whether the two will eventually get married have been swirling.
"Vanessa and I have been pretty transparent with our current state and that is, you know, we got engaged in Bachelor world. And Bachelor world is -- it has its complications, especially while you're dating other women," he explained. "So, not the best way to start things off!"
"Vanessa and I are trying to take a very healthy approach into our relationship, and I think that the best way to do that is to try to be very honest with each other in that situation," he continued. "And that situation is, we love each other very much and we have a really great foundation. There's still a lot for us to learn about each other."
Viall told ET that even though they're taking things slow right now, getting married is "the plan."
"Of course there's going to be a wedding," he confirmed. "But right now, we're just focused on our relationship. Everything will come in due time."
As we patiently wait to see what moves #TeamBabyGotBach pull out during week three of Dancing With the Stars, airing Monday at 8 p.m. ET on ABC, watch the video below to hear the latest update on Chmerkovskiy's injury.