He's shared on-screen kisses with beauties such as Victoria Principal and Suzanne Somers, but Patrick Duffy only has eyes for one lady.

"The one I kiss off-camera every night before I go to sleep," the 65-year-old assures Closer, referring to wife Carlyn Rosser, whom he wed in 1974.

And the actor, who returned Aug. 18 as Bobby Ewing on TNT's Dallas reboot, feels as blessed on the job front (he's a repeat guest star on Amy Poehler's new NBC comedy, Welcome to Sweden) as he does in his private life.

Exclusive: Patrick Duffy Opens Up About 'Dallas' & Playing Bobby Ewing for 35 Years

"I've never had more fun in my marriage than I'm having now, and I anticipate that being the case until she buries me and marries somebody else," he jokes.

So what's their secret to 40 years of wedded bliss? "I don't know," Patrick admits, "but I literally don't think I've had an argumentative conversation with my wife in the past 20 years, which isn't to mean we don't have different points of view."

The Step by Step star lovingly adds, "There's still passion and there's still friendship."

Although his wife is 10 years his senior — "She is a cougar! I was 22 and she was 32," when they first met — Patrick tells Closer he was "the happiest man on the planet" when he began dating Carlyn. "Now she's 75 and I'm 65, and I still am [the happiest man]," he gushes.