Being in a relationship is pretty exhausting. It requires devotion, care, attention, love, and respect. Do you think you got all these ingredients in your relationship? Are you happy with your partner?
If you feel that your relationship is a source of pain, and your partner no longer recognizes the genuine definition of love, then something is wrong. Sometimes, the issue is cheating. But the question is how to know when your partner cheated on you?
No one can tell you the answer for real. Sometimes, a cheating partner decides to become so for no reason. Everything might be going just fine, and you are having a nice, serious relationship. It is very hard to define the exact reasons for cheating.
But this should not be tolerated nor justified at any rate. The best way to catch a cheater is counting his or her countless lies and excuses to travel every now and then.
It is very important to stay calm and deal with it. But some people lose their nerves and start thinking of revenge. They may make foolish mistakes that you are about to know.