EXCLUSIVE: Heather Dubrow Reacts to Friends Yolanda and David Foster's 'Incredibly Sad' Split: Reality TV Is H

'The Real Housewives of Orange County' star and her husband, Terry Dubrow, have known the Fosters for years.

Heather and Terry Dubrow’s marriage is stronger than ever, but that doesn’t mean The Real Housewives of Orange County stars weren’t shaken by the news of Beverly Hills couple Yolanda and David Foster’s split.

MORE: Inside Yolanda & David Foster's Shocking Split: He 'Always Put Work First'

“Incredibly sad,” Heather told ETonline on Tuesday night. “Very, very sad. We met them before any of us were on reality television through some mutual friends, and they were always a lovely couple.”

The Fosters announced their separation in a joint statement to ET just hours earlier, saying, in part, “We are grateful for the years we've spent together and believe wholeheartedly that we did our best.”

“I think Yolanda's an incredible mother,” Heather said. “I'm sure the timing of the announcement had something to do with her children, especially her son [16-year-old Anwar Hadid], who's still at home with her, and protecting them. You know, I just wish them both the best.”

WATCH: Yolanda Foster Hints at Marriage Troubles on RHOBH Premiere

“When I hear about people breaking up,” Heather continued, “it makes me very sad, and it makes me introspective and think, 'OK, what is it that we're doing? Are we OK?'”

Heather and Terry agree -- reality TV puts added pressure on relationships.

“You expose things to the public that you normally wouldn't expose, that you could sweep under the carpet,” Terry told ETonline, “Now everyone's commenting about, and little things can have a way of being magnified.”

“They’re polarizing,” Heather said. “Let's be honest, marriage is difficult, in general. Marriage in the public eye is crazy … You have to deal with tabloids and all that sort of thing, but marriage on reality television?”

WATCH: Inside RHOC Star Heather Dubrow's 20,000 Square Foot, 14-Bathroom Mansion

“I think being on a reality show is a test,” Terry added. “If your relationship is solid, you stay solid. If it has chinks in your armor, those become major cracks.”

“But the problem is, every marriage has ebbs and flows to it,” Heather noted. “So, when you're on television, especially on a reality show, when you're having an ebb, it's hard -- we had an ebb, you know, I think our second season on the show and it was so hard.”

“Yeah, but we never came close to breaking up,” Terry clarified.

“No, but just having it out there and having people talk about you in that way is so upsetting,” Heather said. “And then you have children? It's hard. It's very hard.”

WATCH: Housewives Happy Hour With Orange County Star Heather Dubrow: Champagne, Collette and Cursing!

ETonline caught up with the reality stars at The Abbey’s 6th Annual Christmas Tree Lighting in honor of World AIDS Day.

“We're incredibly honored to be here,” Heather said. “I was so excited when they asked me to light the tree here at The Abbey. I mean, it's an institution in West Hollywood. It's World AIDS Day, and obviously this entire event is benefiting The Elizabeth Taylor AIDS Foundation.”

“One of the things I love about the foundation is that Elizabeth Taylor's trust underwrites 100 percent of the costs for the foundation,” she continued, “so that every dollar that's donated goes directly to people that need it and that, to me, is incredible. She was such a humanitarian in life and in death, her legacy continues.”

For more on the Fosters surprise breakup, check out the video below.