He cheated. He says he's sorry. Should you give him another chance? Cheating involves some kind of sexual activity outside the marriage, but it's not necessarily the sexual encounter that's hardest to get by. It's the betrayal of trust. Whether you should try to move beyond the hurt, anger and disappointment a spouse's affair triggers depends on a host of factors.

Emotional Intimacy Shattered

When the level of trust declines dramatically in a relationship, it cannot be easily and swiftly topped up. According to clinical and forensic psychologist Stephen A. Diamond, Ph.D., trust, not love, is the glue that holds a marriage together . Once your partner has lied, manipulated, deceived and otherwise made a fool of you, the emotional intimacy of your relationship is shattered. This is a very difficult dynamic to restore in a relationship, but it can be done if you decide that your spouse deserves a second chance.

First Time Offender

If this is the first time your spouse has strayed, you have more reasons to consider working things out. The circumstances of the infidelity are obviously important to your decision. If the "first-time" affair has actually been ongoing for years, it will be much more difficult to work through than a one-night fling. Whatever the dynamics of the situation, you should consider trying to mend your marriage only if your spouse confesses what happened, assumes responsibility for it, and asks for forgiveness and another chance.

The Habit of Infidelity

Infidelity becomes a habit rather than a slip-up if it happens repeatedly. While the decision whether to forgive and move on is always your own, consider whether you are playing an enabling role by forgiving your partner time after time. If your spouse is suffering from a condition like bipolar disorder, substance abuse or compulsive sexual behavior, it may be reasonable to stand by him while he gets treatment, but repeatedly accepting proclamations of love and contrition after each new affair may not be in your best interests.

Forgiveness as a Two-Way Street

The good news is that many spouses are able to work through infidelity and come out the other side with a stronger marriage. According to psychotherapist Frances Cohen Praver, Ph.D, this is only possible if you, as the wronged partner, truly can forgive your spouse. But, working toward forgiveness is a two-way street . Your straying spouse must be fully invested in saving the marriage and be willing to journey with you into preexisting relationship problems that may have played a part in his acting out, such as poor communication, loss of intimacy, hurt feelings or festering resentments.