Divorce Predictor #5: You are the only smoker in your marriage.

If only one partner in a marriage is a smoker, the couple is 75 to 91 percent more likely to divorce than married partners who are fellow smokers. According to a study conducted by the Melbourne Institute of Applied Economic and Social Research, the more similar people are in their values, backgrounds, and life goals, the more likely they are to have a successful marriage. Many dissimilarities between partners can increase their divorce risk, from age to ethnicity to unhealthy habits such as smoking.