ET's Katie Krause sat down with the former Grey's Anatomy star at the Dempsey Center in Lewiston, Maine, on Friday, where he opened up about making time between acting projects to support the cancer facility -- which he started in honor of his late mother, Amanda -- and be present with his kids and wife, Jillian Fink, to whom he's been married for nearly 20 years.
According to Dempsey, time is precious when it comes to keeping his marriage to Fink strong. The pair, who reconciled soon after Fink filed for divorce in 2015, and officially called off their split in 2016, share three kids: 16-year-old daughter Talula and 11-year-old sons Sullivan and Darby.
"Getting quality time together in a relationship -- especially with three children, everyone is running around trying to get them to sporting events or school activities, getting them prepped for college or all that -- couples have to figure to get date nights," he noted. "That is what it is about."
"We are growing together as a couple, individually, and as a family," Dempsey said. "The older you get, the more you realize how little time you have, and [how] you want to make the most of it."
The actor was with his whole family over the weekend as they celebrated the Dempsey Challenge, a two-day fundraiser for the Dempsey Center, which provides a personalized approach to cancer prevention, education and support, and provides services at no cost to those impacted by cancer. Dempsey founded the facility 10 years ago. His mother, Amanda, died of ovarian cancer in 2014 after a 17-year battle with the disease.
"They got in late last night from California. They had to go to school yesterday," Dempsey shared of his kids. "But they're here. They look forward to it every year."
"[I hope it teaches them that giving back is] the most important thing in the world," he added.
The Dempsey Challenge raised $1.2 million this year, not counting the donations collected during registration and raised during the event, according to the Portland Press Herald.
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"It's always very emotional for me to come back here, because there's so much emotion, especially on Challenge weekend," Dempsey said. "I try to get back once a month if I can, to come to the center. There's so much work to be done ... and I just love the spirit of being here."
"This is real life, and when you encounter someone who's just been recently diagnosed and they step off the elevator and they come here for the first time, that's a profound moment for both people -- for myself and for the client coming in," he said.
"I really love doing this work," he continued. "And I think it's very special. It's very moving to me and I love it. This is how life should be, and especially in a world that is so full of conflict and so polarized and partisan, that when we come together as communities and we come together that that can be transformed and things can happen. That spirit is alive and well here in the center, and certainly this weekend at the Challenge."
Tune in to ET on Wednesday for more of our exclusive sit-down with Dempsey, and see more on the actor in the video below.