there are different situations. Like you meet the same man and think he's perfect and I want him to live life, but it is later revealed that he is not so perfect, he was just playing with you and wore the mask of a good, it is possible to get some benefit. Well, you certainly disappointed, because I want to trust, but frustration and passes that trust. The relationship should vigilant to look at the person and not to close their eyes to obvious cases of cheating, giving him justification in these actions. you have to first and foremost love myself.