If you know your partner for a long time, understands the nuances of his behavior and habits, it certainly can feel that something was wrong on an intuitive level. Frequent delays at work and travel on the weekends - too obvious grounds for suspicion, which is not even worth mentioning. Note the more minor but important details. Your loved one may suddenly become suddenly alert and give gifts without cause. Coming home, he mutes the phone. Appeared on his computer password, and in the car otherwise sidelined passenger seat. He takes an interest in new music, asks unexpected questions, find fault with their appearance, offers new sex positions ... Such details may not mean anything at all. But if they are too much - it is at least reason to guard.
As a rule, the relationship suddenly pop up on the side and at the wrong time. Even if you thought that, theoretically, you are ready for such a situation, the reality may look different. First of all, decide the main forgiven you your life partner or not. Will depend on further developments.
If you too love this person and internally ready to forgive him, understand and be sure to find out the basic details of his connection on the side. If it was a one-day affair - make the appropriate conclusions. However, if your partner has had a long relationship with gifts, recognition, joint leisure, you should seriously consider whether you need a man.
If the partner relationship started on the side, do not humiliate myself wrong behavior. It is not necessary to avenge the "base razluchnitse" call and understand, to arrange a tantrum to "hero-lover", and also make a lot of other stupid things, which you later regret. If your principal position - to leave, do so immediately, without unnecessary scandals and clarification.
It happens so that the relationship on the side - not just cheating, and indeed the new love of your partner. Perhaps your relationship has long outlived their usefulness, or the man just does not want to admit that the feelings are gone. Trying to keep a loved radical methods - from pregnancy to blackmail intentional suicide - not the right way. Chances are good that it will take you to an even more tragic consequences.
If you know about the change partner, take time out for a few days. Use this time to sort out what had happened and in a calm state to take the right decision.