8. You're in a new situation. Have you recently lost weight, started a new job or taken up a new hobby? You're excited about a new phase in your life, and, intentionally or not, your spouse may be getting left behind in favor of someone who is a part of your new lifestyle.
Cheating alternative: "New changes bring new challenges, and it's easy to shut your partner out and feel like he just wouldn't understand," says Kerner. "Make your husband or wife part of your team. You'd be surprised how much a spouse can understand, support and advise. Whether it's a new job, a new hobby or a new diet, you can still be inclusive."
9. Your spouse is not into sex. When two people have very different levels of libido, this can cause difficulties. When one party never feels like making love, it can cause a real rift in the fabric of your relationship and cause you to go looking elsewhere.
Cheating alternative: Before looking outside the marriage for fulfillment, be sure to communicate with your spouse and see if a compromise can be reached. "Couples need to own the differences and then find compromises that allow the lower -desire person to meet the higher-desire one at least halfway," says Britton.
10. Because your marriage has become long distance. It's difficult enough to maintain a happy marriage when you're in the same house together. But if one of you has to be away for a job or military service, the distance can put a strain on things. You may be feeling lonely and start looking to someone else to fill the gap.
Cheating alternative: "Absence can and should make the heart grow fonder, and luckily there's phone-sex, sexting and even computer-enabled sex toys that can keep you in touch with the sexual side of your relationship," says Kerner.
11. Because he cheated on you. Your spouse cheated on you in the past, but part of you has not truly forgiven him. You may be looking for revenge, and so you tell yourself stepping out on him will even the playing field.
Cheating alternative: "Revenge is never going to get you the life you want; it's a reactive not a proactive mode," says Britton. "Focus on what you want to have again in this relationship or get out of it.
12. You're overcome with desire. You value your marriage, and you love and are attracted to your partner. You may even have a great sex life, but these days, someone else is catching your eye and putting butterflies in your stomach. The nagging thoughts of what it would be like won't go away.
Cheating alternative: "Flirtatious friendships can easily spiral out of control, so watch out if you're spending too much time with the object of your fluttering stomach," says Kerner. "On the other hand, many women fantasize sexually about other men, even when they're having sex with their husbands. Nothing wrong with a fantasy, just don't turn it into reality."
Written by Ronnie Koenig for AOL Health. Read more: