LOS ANGELES — With Valentine's Day around the corner, Patrick Dempsey is opening up about the keys to a successful relationship.

"Marriage works best when you're completely open with each other, and free to be an individual, and strong enough to go off and do your thing," the 44-year-old actor, who has been married to his second wife, Jillian, since 1999, tells Reader's Digest.

Dempsey says the couple, who have three children together, still manage to keep the sparks alive in their relationship.