Catherine Zeta-Jones recently shared a video of her family dancing together. While hubby Michael Douglas swayed with daughter Carys, Catherine boogied with son Dylan. “Our family vibe,” she called it.

These are joyful days for Catherine, 52, and Michael, 77, who will celebrate their shared birthday on September 25. “The thing I’ve learned about getting older is you can’t take love for granted. You protect it, nurture it, and it grows, and after one’s initial physical, emotional aspects, it becomes deeper,” gushes Michael.

The couple hope to celebrate their birthdays with their children — although it’s getting harder now that Dylan, 22, and Carys, 19, are out on their own. “They are such proud parents, but letting go is a huge part of parenting,” says a friend. “They’ll probably go out for a nice dinner, or stay at home, order food in, and blow out a few candles. Like most years, Michael will pick up the cake from a local bakery that Catherine loves.”

Now that their children are pursuing their own lives, Catherine and Michael have more time to themselves. “They miss having kids in the house, the chaos of their friends visiting, and all the comings and goings,” says the friend. “They’re reading more, watching films and streaming shows together — although they joke that they don’t have anyone to help them with their technology anymore!”

In addition to raising two children, the couple, who were wed in 2000, have weathered some storms. Michael underwent treatment for tongue cancer in 2010 while Catherine has been open about her battle with bipolar disorder. The pair separated for a brief time in 2013 but found their way back to each other. “The constant is love and respect,” says Catherine. “We’ve never, ever, lost our sense of humor, and we enjoy each other’s company.”