When I interviewed long-term couples who said they were very happily married, I was surprised at how many of them had overcome affairs. I detailed that study in Loving in Flow: How the Happiest Couples Get & Stay That Way, and later began writing a “Love Advice” column. After 8 years of responding to lovelorn letters, I’ve compiled some hints that a husband or wife may have been or will be unfaithful in the near future. 
6 clues to infidelity:1. Your husband or wife has begun keeping secrets. If he walks into another room while on the phone, or shuts down the computer monitor (or hurriedly presses a couple of keys the second you appear), such secretive behavior means your mate is beginning to put up a wall around him/herself in case it may be needed one day.

2. Arguments flare up for no apparent reason. When your mate gets angrier than is warranted, there is often something else going on under the surface issue. That anger and the argument itself may be a way of making it “obvious” that YOU are the problem in this relationship.
3. He/she insists that you’re not “growing.” While your mate is growing and developing new interests, it is claimed, you are lagging behind and unchanging. If this is not based in reality, and in fact, your mate’s only new interest is in watching new kinds of porn, beware.
4. Your mate still believes in magic and soul-mates. Mature partners adapt to the reality of long-term love. Some men and women, though, persist in thinking that what they actually have is second-best, and that “the one” is still out there. How does your mate respond to movies that idealize love vs. “ordinary” life? Does one of you blame the other for the diminishment of sexual frequency? Does either of you have a habit of “if onlies,” as though happiness can only be given TO a person, without their own hard efforts?
5. One of you feels subtly abused all the time. Constant criticism, even if couched in gentle “helpful” words, makes you feel judged and found wanting, as though you would have to become a whole other person. Sooner or later either one of you will seek a way out.
6. Your mate has forgotten your early starry-eyed history together.You bring up a thrilling date, some beloved memory or other, and he/she can’t recall it. Such glowing memories cause cognitive dissonance in the unhappy present, so they are put deeply away.
Don’t say I didn’t warn you. And if you have experienced something like this in your own relationships, what were the clues you wish you had noticed earlier?
Copyright (c) 2011 by Susan K. Perry, Ph.D.