how would you know that your girlfriend/boyfriend is cheating on you

if he's acting strange, always uncomfortable if he's with u, can't look u in the eye...well based on experience, my ex kept his celphone away from me when before he would just let me use his celphone,and when an anonymous caller appeared on his screen, he walked away and answered it. i never confronted him, knowing that he'll just be caught at d ryt time. and it happened! it was painful but later on, i was thankful that it happened...i dont deserve a guy like him after all...such a loser.

if he/she behave in extremes i mean if try to praise you in excess or ignore you be on alert he/she is playing games with you