Arnold, 39, who began experiencing bleeding, contacted her OB-GYN while in India and realized she had to return home to Houston for medical attention while Klein, 39, stayed behind with son Will, 3, to get Zoey's paperwork finalized and bring their 2-year-old daughter home.
"We worked hard to get together," Klein says. "I love my wife. It broke my heart to put her on the plane and not to be next to her to make sure she was doing well. I stayed up all night, tracking her plane, watching Will and comforting Zoey when she would wake up."
The couple's adoption of Zoey and Arnold's diagnosis and cancer battle will be part of their new season on TLC's The Little Couple, premiering Tuesday, March 4, at 10 p.m. with a special one-hour episode.
Wanting to educate the public on dwarfism was one of the reasons the couple decided to participate in a reality series, they say. Sharing Arnold's cancer battle was a decision Arnold, a neonatologist at Texas Children's Hospital, saw as an opportunity to educate and possibly help others.
Though the couple have been through one of the most difficult times in their lives, their bond is as close as ever.
"It would take a hell of a lot to pull us apart," Arnold says in the series preview (see above). "Cancer's not going to do that, that's for sure."