It can, but not always. Cheating, if proven, can make a party ineligible for alimony if it is determined that the affair is the cause of the divorce. It can also put a party “on the hook” for paying alimony if it is determined that the affair is the cause of the divorce. Notice the word “can”. Each case is dependent upon the facts presented before the court. So just because your neighbor’s husband had an affair and she got alimony does not mean that you will get it, even if both husbands had affairs. And just because your neighbor did not have to pay alimony to his wife because his wife had an affair does not mean you will have a similar fate if your wife is cheating.
You should also know that the issue of the affair may never come before the court if the evidence of the affair is deemed to be improper. Even if the evidence is presented to the court, the court may not be as outraged as you may be as outside relationships are often a factor in divorce cases, and courts are rarely shocked by their presence.
If an affair is a factor in your marriage and you are contemplating or facing a divorce, immediately mention the existence of the affair to your attorney and discuss your options. Each case is different because each family has a separate set of facts. As the effect of an affair is a fact driven process, the sooner you get your facts to your attorney, the better the chance that the effects of the affair can be properly managed.