There are four factors that seem to have the greatest influence over whether a spouse will cheat or not. These factors are pretty basic and probably won't surprise many people. They are the same factors that probably influence caveman and women, too. Human nature just doesn't seem to change!
Good Looks, Charisma & Wealth – Just like the peacock, men with beautiful plumes often get their choice of pea hen. For women, those described as "sex-pots" and "hottie’s" are often sought after by men – ring or no ring. No new information here. That’s why people tell you that, if your middle-aged hubbie is suddenly sporting a new look, you might want to start asking some questions; and same guess for a middle-aged women. Better to marry dowdy and shrek-like than dapper and gorgeous, charming, and rich no explaination needed here.
Opportunity and Free Time – Couples that lead fairly separate lives – social lives, careers, travel – are more likely to cheat than couples that spend most of their time together. Of course, couples that spend every minute together can get awful sick of one another and may never grow as people. Somewhere in between suffocation and total freedom is probably best.
Risk Taking Personalities – People who like a thrill tend to get themselves involved in extramarital affairs more than homebodies and cautious people. If you’re married to one of those adventurous types, better look into couple’s sky diving or bungee jumping... or you might be in for a sad surprise.
High Sex Drive – Obviously, if you don’t like sex, you will be less likely to seek it out! People who love sex, and those that have an “addiction” to the excitement, thrill and titilation of “the kill” are at great risk of cheating. No matter how wonderful the sex life of a married couple, it can be hard to compete with the "new" (for some people!)
Feeling Neglected, Unappreciated – Of course, unless the cheater feels somehow entitled to a harem or stable of studs, most individuals engaged in extramarital sex are truly unhappy in their marriage. They often feel neglected, both physically and emotionally. They talk of being unappreciated, misunderstood and unloved. This is open door for extramarital affairs. Love the one you're with!