First, you need to distinguish the facts from the stories of others, often a girl trying to defame her friends or your competitor who only wants to criticize you. Therefore, until they saw nothing, consider treason unproven, even if she says that has changed. Sometimes girls are trying to show that they are necessary and interesting, come up with stories about the affair to annoy the man. Stick to the presumption of innocence. That is, until nothing is proven, take no serious action.Secondly, if adultery has taken place, check whether it is connected with the structure of personality girl. Part of the blame always lies with the man, but not all wine. Perhaps you have chosen to favorite girl the demonstrative type that craves male attention, and she just couldn't stop in time, went from harmless flirting to more intimate relationships. To judge her too harshly for it is impossible, it is its natural quality, so women need to constantly thrills. So cheating is not repeated, and fill her life with unusual events, come with a rose in his teeth, buy new clothes and organize candlelight dinners. This fee is not too high, because that's what girls are demonstrative of the type usually look most impressive and could become the hallmark of her husband.Thirdly, look for its share of the blame. Men often blame that often begin to accept the beloved for granted and do not pay sufficient attention to the development of relations. Maybe the girl thinks it is time to move to the stage of legalizing your relationship, but you, as the person thorough, I feel that while financially or morally are not ready. A womanizer who seduced her, told her about the marriage and future children.So after deciding if you can forgive, in principle, seriously consider and discuss the issues of development of relations. Many women rightly believe that until they are married, they have the right to communicate with anyone. So if a girl means a lot to you and you can forgive – make an offer and live happily ever after. If not, then it is better to end the relationship, so be honest.