One warning sign would be that your relationship is totally sexless, says sex and relationship therapist Megan Fleming, Ph.D. — or if you're having sex less than 10 times a year. After all, she says, it's intimacy that separates a romantic relationship from all other sorts of relationships you might have. "When that's going out the window, it's a really big red flag." Jane Greer, relationship therapist and author of What About Me? Stop Selfishness From Ruining Your Relationship, says that a lack of visible physical affection — like kissing or hugging — is also indicative of a real problem.