Why is this?
Most Helpful Guy
Same reason people cling to unhealthy toxic relationships or relationships they deep down know is on the rocks but have a scarcity mentality and feel like that this is the best they can do. It could be oneitis, it could be a bit of insecurity, it could be that you are too trusting. "I will never do it again" could have truth to it, especially if the cheating happened during a black out drunk episode, or if the cheating wasn't particular sexual but only flirting or kissing. Other times the "I will never do it again" begging act shows that the cheating wasn't because the cheater was looking for love elsewhere, but was seduced or got caught up in lust (usually men). If the cheater doesn't feel any remorse, obviously the relationship will never be the same it is best to cut ties, especially if the affair was out of spite.
This usually comes down the fact that men usually cheat because either 1) their woman isn't sex positive enough / doesn't provide him with the kind sex (attitude) he craves or 2) poor judgment / spur of the moment seduction / weak will. For women it is usually 1) dissatisfaction with the relationship or 2) revenge / out of spite.
Notice, communication would have probably prevented all of these situations. People who get back together after cheating and realize that more communication is needed, start to open up to each other more, express their feelings in a constructive and nonjudgmental way, discover themselves all over again, and it makes them all the stronger because of it.
Those who look at the act as a heinous transgression without looking into the reasons why it happened, especially when the cheaters are remorseful, tend to break up without ever realizing that it may have been some failure on both partners that lead up to the cheating.
Maybe he cheated because he took you for granted and it took this moment to make him realize how much you mean to him. Maybe he cheated because he has problems with binge drinking and you will need to decide whether it worth supporting him in putting his partying ways behind him. Maybe she cheated because you didn't pay attention to her enough, didn't make her feel sexy when she went out of her way for you, didn't show appreciation, didn't put her first. Maybe she cheated because she isn't ready for a long term relationship (time to move on), or maybe she cheated because she is a spitfire who is vengeful (run!)
Every situation is different...
Most Helpful Girl
Cheating doesn't make people stronger. Don't believe in that lie. The overall outcome of having to work together to put back the pieces and the process of healing is what makes couples strong. Never should it be condoned or be acceptable.