If he stops telling you where he's going, comes home later than he says he's going to, comes home smelling like perfume, lies to you about where hes going, what hes doing....it all depends on what age group we are talking about here....how old are you?

u feel like someone is watching him like his old girlfriend and he does thing that u don't see him do when the old girlfriend is not watching him.

If you think that a guy is cheating on you, look for some specific signs. 1. Is he not truthful with you? If he is suddenly lying and making excuses for himself, he could be having some life issue he does not want to talk to you about or he could possibly be divulging his emotions to someone else. 2. Is he showing you less affection? If he is showing you less affection, he is quite possibly cheating on you. Although this can be attributed to stress, less affection is a pretty good sign. Does he hug you goodbye instead of kiss? 3. Is he finding excuses to not be with you? This is also a pretty straight answer. If he is not wanting to be around you, he could feel that you have spent too much time recently or he could be making time for someone else. 4. Has tension come up in your relationship? This can happen if he feels guilty and he will become testy around you. If you wish to be absolutely sure, find a time when the two of you are alone and tell him that you just have to know. If he says yes, well, try and still be his friend. If he says no and provides no reason, trust him for a few days. It could be that he just has something major in his life which is going wrong and he could not be interested in talking about it.

Trust me you will know if he's cheating, you just might not want to accept the facts.....

Well when my now ex cheated on me he stopped saying things like 'i love you', got more quite, didn't talk about what he thought (for example stuff that bothered him) umm what else... he didn't start a conversation with me, avoided me for awhile ... i cant remember anymore things

i don't think you can know for sure (unless you walk in on them or have "cheaters" follow him around), but most the time, it seems like people get a gut feeling about it when their partner is cheating. usually, their gut is right (unless maybe they are just the jealous and/or paranoid type).

well, he's doin so many excuses like for instance he cant be with you coz he is busy..but then..even if a guy is too busy,, if he's really into you he would find a way for both of you to have time for each other. and also..he is cheating on you if he even cant look at you straight in the eye! you'll noticed for sure...believe me..ive been there! :)

Generally the scratch marks and th smelling like sex gives it away.

One big clue is when they all of a sudden have to do a lot of overtime, especially if their coworkers do not. This is pertains mostly for boyfriends because you would not see their paycheck or pay stubs. For husbands, they need to run errands alot and never want you or the kids to go.

You start to notice a lot of white lies. He becomes defensive when questioned. A guy who doesn't exercise much suddenly becomes interested in toning his body. He starts wearing nicer or cleaner (!) underwear.

He starts to bath directly he gets in dresses up better shaves all the time,lots of aftershave. Not in much makes sneaky calls,doesnt want to make love to you,lots of things like that!

I agree with miss zee. When the gut feeling was mentioned. I've been there and definately felt it inside my stomach before I caught my partner. I actually found out that very day.

Every guy is different but for any woman who truly knows her man, you can just tell. You will notice changes in him overtimes. These changes can range from his attitude, to the sex between you. You'll also notice little things like he doesn't go anywhere w/o his cellphone including the bathroom, he starts coming home late or hanging out more w/ "the boys", he'll break plans he has with you at the last minute, things like that. The definite giveaway is when he comes home with lipstick on his shirt and smelling of woman's perfume.

You will know he's cheating if the phone calls suddenly slow down and it seems like when you do talk you have nothing to talk about.

when he is really pushy to get you out the door. for insistance. i just went to a family wedding away from home.. i was suppose to spend the night up there but when i realized that he hadn't phoned the entire night i got really worried. So i decided to come home i searched all his friends houses and called them and even went to the police to file a missing persons! i was terrified.. I finally found his car but he wasn't in it. i left a note on his windsheild saying how worried i was.. I searched until 4 in the morning. He never came home that night. He phoned me at 11 the next day.. and i realized he had stayed at a "friends" house.. but i know this friend also has a sister that is very interested. I told him he had a lot of explaining to do.. he agreeded. I don't need him to say it because i know in my heart he was un-faithful.

he forgets to logg off his email account ..lol

You'll know it in your gut...When you get that feeling, start investigating and find out all of the facts before you bring it to him/her...

If he starts to smell different like her or if he smells showered when he comes home, has his cell on silent, if you notice female hair on him that are not yours, if he is either too nice or becomes easily frustrated, there is so much small details, but find out first before you tell him.

ask and get really friendley with his guy mates they are bound to know something! one of them is bound to slip something out! sooner or later and give it time to you are really sure gather all youe evidence and always follow your head not your heart as they can blind you from the truth.

Ooh, ooh, I know this one... R U Ready? 1) He can never make time for you except late at night. 2) He cancels plans with you. 3) His penis smells or tastes funny (seriously). 4) Unusual long hairs on clothes or in car. 5) Stains or Oder on the inside of his underwear where his penis makes contact. 6) Strange perfume or scents on his clothing 7) Does not call you and claims his cell phone battery died. 8) He claims he is working late or hanging with the boys. 9) He keeps getting calls while you are together that he feels compelled to answer and have conversation "in-private" 10) Trust your gut, it is usually right. TM