Treason on the part of the girl usually takes them by surprise and is perceived by many guys more severely than a break in relations. Such an act is comparable to betrayal and is capable of destroying long-term relationships, long-term plans and rather strong feelings, but what steps to take depends on the feelings and situation, as well as on the outlook on both partners. Variations of events are infinite, but they can be typed as to how the guy is informed about what happened.
In the clearest and simplest version, the girl herself will say that she was wrong - there is no point in looking for evidence, accusing of dishonesty, but it makes sense to find out the reasons. Moreover, both the motivation for treason and the recognition motivation are important - there are frequent options that the girl regrets her misconduct, but tries to refrain from lying or does not want it to come up somewhere. For some girls, cheating is a convenient way to end a relationship, in which there is no need for a long time to explain their position. With such a course of events, it is important to find, in addition to pain, also thanks for frankness.
In the case of the code, the guy himself witnessed treason (he saw a girl kissing another, or even found them at home) then there were no options for excuses either. The girl's behavior after betrayal is hard to predict, two cardinal options are possible - either she ends the relationship, or apologizes and promises to fix everything. How much to believe, and whether it depends on sincerity, but it is important for a guy to remember that he was initially deceived, and he himself became an accidental witness to the betrayal.
Among the unconfirmed changes can be the guesses of the guy himself, the stories of mutual friends and neighbors, the strange behavior of the girl, random coincidences and other options that are not facts. In the presence of such implicit treason girls, the main thing is not to succumb to the opinions of others and their own emotional outbursts, but to evaluate the situation as abstractedly as possible, it is even possible to discuss your assumptions with her. It is necessary to evaluate the facts, talk to the girl, ask the evidence from the storytellers. Remember that in many articles women are advised to cause jealousy among their boyfriends if they have lost interest in them, so maybe this is staged. Perhaps the boy’s prior intimate relationship experience contained adultery, so jealousy flares up quite often, especially if he has no control over every step the girl has. This is a serious and extremely important job - to determine the actual presence of adultery or slander against a girl, because in one case you risk losing and offending a loyal person, in the other you allow yourself to be deceived.