When you pass the first shock of betrayal, talk with your partner openly, calmly and without emotion. Find out why someone you were needed. Just avoid details, spare his dignity.
After this conversation, take the fact of treason as a circumstance that is not correct. Stop torturing yourself the question "why it happened to me" and "for what I do." It was all, nothing to fix. Life does not end here, but on the contrary, may open new perspectives. If you get through this time and keep the family together, the experience will help build errors more harmonious relationship. And if you decide to leave, then you have come new opportunities.
Then you have the most difficult thing - forget everything that happened. Just "erase" the file from memory. Difficult to force myself not to think about it, displaces other those thoughts, positive. If you have kids - to pay all of his free time to communicate with them, "Load" campaigns themselves in different places, make sure that there was no time to think about the past.
If you have the opportunity, the first time after the incident Live a separately. Try to analyze your mistakes, give the person responsible for his act of betrayal to survive and to draw conclusions. For all takes time. If this is not possible, stop at the time of sexual intercourse. Often deceived wife make the mistake of trying to prove in the bed that they are better lover or mistress. Do not do it, you're out of the competition, you should not compare.
If you were able to keep the family together after infidelity, never thought the perpetrator of his blunder. The relationship of this does not improve, he or she will feel humiliated, and you will find yourself again in the same emotional "shock". For any subsequent conflicts be wiser Keep silent about the past.