how u know that yur boyfriend is cheating on u?

These are the signs:
1) He's not as sweet as before when ur together.
2) He misses to call you back when u leave msgs.
3) He always makes excuses to see you.
4) He forgot important dates in your life (b-day, anniversay, etc.)
and most of all he never initiates to kiss you...
Girl, watch out!! If confirmed, break up with him right away, before he makes the 1st move.

send the show "cheaters" to spy on him.

does he talk on his phone where you can't here? Is he often gone to unexplained places, does he seem more distant? check for subtle things guys don't think about like make up on his shirt or forign hair in the car or check for any new markings on his body, and belive people when they say, you will know even if it is just a nagging suspision. It's usually right on! sorry to say

ask him about it and if he can't look you in the eye when he answers, he is cheating. also look for suspicious messages in his cell phone. and i agree with the other girl, you have to watch john tucker must die

i don't know if there is a sure fire way to know that but.. There are signs, such as: being distant, secretive, talking on the phone in the other room, cancelling plans w/ you to spend time with the buddies... thing of that nature give you a good sign.

If he's happy, he's probably cheating.

If he gives you any reason at all to beleive that he is cheating on you, he probably is. Break up with him.

Well, if hes cheating on u, then he might not answer your calls, say s he will go hang with his"friends" something like that or he ignores you.

If you think it that strongly....then
"maybe" he is.

sniff his shirts for perfume :)

Simple..watch John Tucker must die. =]

you know