Actress Nicole Kidman refuses to tell reporters she's happy in her marriage - because she doesn't know what will happen between her and husband Keith Urban next. The Moulin Rouge! star admits she and her spouse of 16 months are "deeply in love" but she considers it bad luck to publicly reveal her good fortune when it comes to matters of the heart. She tells American magazine Interview, "I don't ever say that. Partly because interviews are done in advance and you never know where something's going. "People's lives together are complicated and beautiful and that's what they should stay. They're very quiet... They don't need to be broadcast." Kidman adds, "My husband and I are committed to each other and deeply in love. That's how I would put it. We're working on staying in that place, and hopefully we will for the rest of our lives." Kidman and Urban's marriage has already been tested - the country star checked into rehab last year (07) for an alcohol abuse problem - just months after the could had wed.