"I just burst into tears because I was scared and frustrated," Rosenbaum told ABC News' Adrienne Bankert about his battle with Guillain-Barré syndrome, a rare neurological disorder.
"I have to tell you, when he burst into tears, I have never seen him cry," added Hebert Rosenbaum. "Never."
The couple, parents to son Fordham Rhys, 5, and daughter Essex Rose, 3, first noticed symptoms in Rosenbaum last month when he was having trouble with basic tasks like carrying a pizza, getting dressed and opening doors.
The hardest part for Rosenbaum, he said, was how his then-undiagnosed illness was affecting his kids.
"I can't hug my kids, pick up up my kids, do anything for my kids," Rosenbuam recalled. "I don't want my kids seeing me like this."
Rosenbaum, 42 -- who met Hebert Rosenbaum, 34, during production of the show's seventh season -- was soon diagnosed with Guillain-Barré syndrome (GBS), where the body's immune system "mistakenly attacks part of its peripheral nervous system," according to the National Institutes of Health (NIH).
GBS can cause everything from brief weakness to "nearly devastating paralysis," according to the NIH, though most people ultimately recover. The syndrome affects around one person in 100,000 each year, can strike at any age and affects both men and women, according to the NIH.
Rosenbaum said doctors told him he was diagnosed with GBS early enough to be able to make a full recovery. He is currently undergoing physical therapy five days a week.
The couple, who renewed their wedding vows in 2018, said the health scare taught them the true meaning of "in sickness and in health."
"It's never that obvious until you're in sickness and you realize the potential catastrophic effect it can have on a relationship, your family," Rosenbaum said.