A source tells ET that Peta Murgatroyd 'spent a handful of nights crying herself to sleep.'
Maksim Chmerkovskiy is home safe in the United States with his wife, Peta Murgatroyd, and their 5-year-old son, Shai, but a source tells ET that the couple now worries about "having to explain to their son what has been going on in the world and about where his dad was."
On Wednesday, Maksim returned to the States after fleeing Ukraine, where he is from, amid Russia's invasion, and was reunited with his family.
"Peta is so thrilled to have Maks home and back with her and their son," the source says. "She has been going through it and has been worried sick and emotional."
Peta is "so grateful" to have her husband back home as "it was a struggle for her and she spent a handful of nights crying herself to sleep," the source notes.
"She was doing her best to hide her somberness from their son because she didn't want him to internalize this or be scared," the source adds.
The source says of the Dancing With the Stars alums, "Peta and Maks have received a ton of outpouring support from their friends and Dancing With the Stars family. They are both incredibly grateful for that."
ET's Kevin Frazier was with Maksim when he touched down in Los Angeles, and the 42-year-old pro dancer was overcome with emotion, admitting, "I just don't want to resent peace somewhere else because of what I just saw, that's the reality. I don't know really what to say right this second."
Maksim, who was in Ukraine to film as a judge for the country's version of World of Dance, also spoke to the press outside the airport, and addressed Russia's invasion and assault on Ukraine's major cities, as well as his own experiences returning to the U.S.
"The reason why Ukraine is standing right now is because of the Ukrainian people, and the fact that the entire world is helping," Maksim said, explaining that this sort of conflict was something many Ukrainian citizens had been expecting for years.
Maksim also gave a "huge shout-out to Poland," where he retreated to before flying to the U.S. "The way I was treated through the whole process of leaving into Poland, I've just got to bow down to the Polish people," he said.
For more on Maksim's journey home, watch the video below.