Allow the Gossip Girl alum to tell you herself.
Admitting the pair have a "normal relationship with all the good and the hard," Leighton exclusively told E! News' Courtney Lopez for the Nov. 21 episode, "We just make it work."
"We're super, super lucky, and I think we recognize how lucky we are with one another," she continued. "We give each other a lot of respect and time and attention and focus. Like, really put our time and energy into a relationship."
And Leighton—who shares 8-year-old daughter Arlo and a 3-year-old son with the O.C. alum—added that, of course, it helps when you genuinely enjoy each other's company. (Catch more of her interview on E! News Nov. 21 at 11 p.m.)
But while she has a low-key romance with Adam, the same can't exactly be said for the characters she plays onscreen. Take her new movie EXmas, in which her character Ali secretly attends her ex Graham's (Robbie Amell) family Christmas because she simply missed his parents.
"This is the heightened reality of wish fulfillment of like, 'My ex, but we do get along, but it just didn't work out, but they love my family and family loves them,'" Leighton shared with E!. "No—real life, you're like, 'That's a stalker. That's not good.'"
Understandably, Leighton would not want to have her former flame decking the halls with her fam IRL.
"I don't even want to like think about that," she quipped. "That would be terrible."
And would Adam even allow it?
"I wouldn't allow it," she joked. "All his exes, I'm like, they seem like pretty good people. And my family, he can have ‘em. I don't think that that would be the case."
EXmas is now streaming on Amazon Freevee.
For a look back at Leighton and Adam's merry and bright romance, scroll on.