A lack of emotional intimacy, physical neglect and abandonment are bad enough reasons to cheat and stray. 
But when it's for reasons of boredom and stems from polyamorous fetishes, preferences for open experimental sex, where couples "swing" due to an ability to "share" someone they love, it's no wonder the word "committed relationship" starts to lose its original lustre. Welcome to the post-internet world, where SUVs, kids, never-ending piles of laundry, a huge mortgage, and a less than satisfactory work life-personal life-sex life balance upsets a relationship's natural rhythm, temping a person to seek pockets of happiness outside a union. Cheating in the new world includes grey areas like flirting, kissing, online sexual communications, webcam sex, and can be anything that breaches a relationship contract and be kept a secret. Adultery seems to have found a scapegoat in boredom and hormonal attraction. But when did private bedroom behavior get so "boring" that people got gutsy and became unfaithful?
 
1. New smells get old
The men we polled have corroborated our worst fears - no matter how hot you are, once you've handled them buck naked, new always gets old. The new feeling, new smells wear off slowly, but surely (no wonder even the hottest celeb couples fall apart). But men say that making love and friendship grow is more important than getting a sex fix from someone else and ruining what they have.
 
2. Monogamy is a mountain too high for some
Let's not be blind to reality. Daily life does put a damper on things and flat out exhausts us by day end. As kinky as you may've felt during a short sext interlude at 1pm, getting home to a tons of chores whilst nursing a migraine from prepping for a 10pm concall with corporate later that night can wipe you out, leaving less energy and enthusiasm to physically bond in the same way as the week before. Now, extrapolate this over 40 years… you get the picture.
 
3. Boredom
But boredom isn't as shallow as it sounds. It probably does get dead boring and the actual routine of same old, same old is worse when lived by the day than when penning it down. Over half a century, people will job hop, put on weight, change interests and attitude. You're literally be having sex with a different person of the same name. But the irony is it can still get boring although the one you love hasn't stayed the same. Love means acceptance of things that thrill you about your partner as well as the things that don't. Choosing not to makes the front door your best friend and mind-mapping an exit strategy as your contingency plan. Of course, if you both can live with the excitement of introducing new lovers into your relationship equation and not being worry about either of you being addicted to someone else's body, then good on you.
 
4. Cheap thrills
If you think harmless flirting is, err, harmless, think again. Don't introduce fuzzy logic because 9 out of 10 times it comes back to haunt you. Cheating may feel liberating initially and the secrecy and sneaking around can be intoxicating. You may feel a sense of rebirth and the rush is like no other. But the headiness subsides just as fast after you're done when duties dictate you rush back to the reality of your daily lives. It may be beneficial to note that affairs of this type rarely end up in a legalized union.
 
5. Hormones
Most people are genuine when they promise to stay faithful. But hormones are to blame for avowing monogamy then crossing over in a split second lapse of judgement. Cheating involves sexual desire, romantic love and attachment, brewing a potent cauldron of "I am willing to compromise and risk hurting my existing relationship." Sexual desire is intense, powerful, and involves lustful, sexually passionate feelings. Its mastery is in clouding one's judgement and encourages risk taking. It's often tied to physical appearance, novelty and "chemistry." And while it steers a person's actions in the right direction early in a relationship, the intensity can be difficult to maintain with that same person over time. Romantic love is a complex set of rational and irrational feelings. It includes hormonal attraction, attachment, feeling "in love" as well as a decision to love and commit.
 
6. Instant decisions
Most of the time, infidelity is driven by circumstances and a hormonal reaction to a stimulus. It usually sneaks in when there's an escalation of dissatisfaction in your union and a lack of communication and personal interest in resolving it.
 
7. Temptation to escape
Like a moth to a flame, burnt by the fire, temptation is a powerful emotion. When placed in certain situations, our hormones get the better of us. Temptation is everywhere these days and to exacerbate things, men and women don't abide by the same rules of self censorship or self control like before. Being fuelled by a millisecond surge of sex hormones is a hard thing to resist and can make you do things that you don't mean to. Don't underestimate escapism as a powerful aphrodisiac. It pushes us to consider the merits of forgetting reality, for a while.
 
Source: Yahoo!