how will you know if your bf/ gf is having affair with someone else?

well i would say if they try to be secretive about their phone you should worry a bit. there is no reason why anybody should have to hide their phone. there are so many ways to cheat via cell phone...calls, texts, picture messages, you name it. that is why i have my husband's passwords to everything and he has mine. it is necessary to have an open relationship

I think you will know if your partner is having affair in other person if you feel that he change in the way he treat you before. He spend less time you now than before and he is not listen on what you say very well. That is also base on my experience. Those things that i say may change depend on his personality. He also get easily angry when there is some discussion that he don't like. If you ask him that if he have other. He will return to you the same question.