McMillan says it's also essential to be truthful to yourself about a relationship, especially if there's a very big reason it's not working. "Chances are you're keeping a lot of the details about him to yourself," she writes of this kind of situation. "Not that you don't talk about him to anyone who will listen... you just conveniently leave out the shocking parts of the story. Instead of being married, he's separated... instead of being nineteen, he's really immature." McMillan says you have to examine what you're saying. "When you hear yourself making excuses this way, wave a red flag in front of your face," she writes. "Because you can be very sure that without some kind of intervention, the relationship is going to run into trouble, and the person who's going to have to deal with the aftermath is you."

Daniel Ochoa de Olza/AP