ABC News' Daisha Riley reports:

Heather and David Robertson have done everything together for 18 years, so when she decided to go under the knife, he didn't think twice about doing it, too.

"You know what, hey, whatever, I am game for it so let's see what happens. It's got to be a bonus. It can't hurt right?" he told ABC News.

Time has been great to their marriage, but it has taken a toll on their bodies.

"Well, Heather has had four children, we have had four children together and you know it takes quite a toll on our bodies," he added. "So if anybody deserves to get a tummy tuck, I think she deserves to get one done."

David has gained 50 pounds over the years and has a double-chin. He opted for a chin lift.

"Well, if you've seen me when we first met and I think that is the image she has of me in her head, I was about 135 pounds and was all muscle and now I am about 185 pounds and there is not as much muscle," he said.

This will be a new chapter in their lives, she said.

"I know we are still young but we are getting older, and just another new chapter, another new adventure," she said.

Dr. Anthony Youn, a board-certified plastic surgeon who specializes in cosmetic surgery, said he is seeing more and more couples like his patients Heather and David Robertson getting cosmetic surgery.

"A lot of couples want to play together, they vacation together, they want to raise kids together. Now they are having surgery together, too," said Youn, director of the Youn Plastic Surgery clinic in Troy, Mich., and affiliated with the city's William Beaumont Hospital.

On the day of their surgeries, David had his procedure first, then Heather.

Six weeks of healing later and the extra skin on David's chin is gone. Heather's baby fat after her four children is non-existent.