Scott Porter's marriage went through a "complete change" when his wife discovered that she had Huntington's disease in her family.
The 45-year-old actor has been married to casting director Kelsey Mayfield since 2013, but when she discovered that her mother had the brain disorder that affects movement, thinking, and behaviour, he noted just how "quickly" it had altered things between them.
He told People: "That was definitely a moment of complete change, as far as the trajectory of my wife's and my relationship.
"It can really tear through families very quickly."
Hungtingo's disease is genetic, meaning that each child of a parent who suffers from it has a 50 per cent chance of inheriting it themselves but the Ginny and Georgia star - who has McCoy, 10, and eight-year-old Clover with Kelsey - insisted that getting tested is a "choice" that must be made by each indiviudal.
He added: "People who find Huntington's disease is in their family have a choice to make: get tested or not get tested.
"Live your life not knowing or live your life knowing that you possibly have a neurodegenerative disease that could take your mind, your body, your balance, your moods, and turn them into something completely different than you are now.
"There is no right or wrong way to go about things."
The Friday Night Lights actor also noted that when Kelsey learned of her diagnosis, that she simply told him she wanted to be around "as long as possible" for her children
He said: "My wife said the words to me: ‘I want to be a mother as long as possible.’ And that was the impetus for her wanting to get tested. It was the right thing. And as her husband, I was so incredibly supportive of that.
"The moments immediately after her positive test were silent.
"She looked at me and she said, ‘50/50 chance. It was a coin flip and it came up tails.."
