How can i tell if my girlfriend is or has cheated

if you have a feeling she probably is... really human intuition is more accurate than you think sometimes...

You can tell if she is cheating on you if she goes out for hours on end, and insists you go to your m8s house or summint. My GF has cheated on me loads of tyms...she even told me that she slept with another boy the saem day she did it... TBH i dont no y im still with her... shes slept with two other boiz as far as i know and kissed about 100 more :v... I've forgiven her loads of times...but i think she has the need for cheating on me. I found the best way to deal with it is to forget...! I never really think about what she has done becuase it sux! I've learnt to live with the fact , mainly coz i know that you cant turn back to time and stop it...

I've found out that she did it before by looking at her MSN chatlogs. Also txts are good to look at.

 When she was out I went on her computer and emailed the chatlogs to myself, then when i went home i could read them. Then if i find something I say it to her. This is what I found before:

[21:16:53] [x]..?a???l?: omg yeh 2day was kinda a gd day bt not in
           terms of me n dan kinda fing...
[21:17:03] [x]..?a???l?: ive cheated on him TWICE 2day josh :|
[21:18:24] -           : lopl
[21:18:24] -           : did u kiss Jonny __
[21:18:33] [x]..?a???l?: no callum
[21:19:03] -           : oh
[21:19:03] -           : ew
[21:19:14] [x]..?a???l?: y "ew"
[21:19:23] [x]..?a???l?: hes beter than jonny...lol
[21:19:45] -           : haha**
[21:20:01] -           : ur a liar btw
[21:20:05] [x]..?a???l?: bwt what?
[21:20:29] -           : becos u said I was the only person u wud
           cheat on Dan with lopl
[21:21:26] [x]..?a???l?: i no...bt 2day was just lyk the perfect tym 2
           get wiv calz cos his gf werent ther 2day..AND i found out
           she cheated on him by sleeping wiv his bm!! so i told him n
           then wen i left apparently they had a phat arguement bt iva
           way...calz still got in wiv me n tried 2 finger me :P
[21:22:37] -           : I dont want to know that :(
[21:23:23] [x]..?a???l?: lol soz bt patback 4 monday
[21:23:29] [x]..?a???l?: *payback

 Also: 

[21:49:50] -           : Lu guess what
[21:50:23] [x]..?a???l?: what?
[21:50:28] [x]..?a???l?: WE HAD SEX
[21:50:29] [x]..?a???l?: lol
[21:50:33] -           : x
[21:50:38] [x]..?a???l?: hehee
[21:50:41] -           : oh right it was an emo
[21:50:47] [x]..?a???l?: lol
[21:50:54] -           : I cant actually believe u were my first
[21:50:59] -           : not that thats bad at all

As you may of told I was extremely pissed when i read that! I went mental and went to one of the boiz houses and smacked him...then ran away lmao.

Anywayz... Just thort I could share this wiv you.

If you cannot ask her and expect to get a true answer, she is not worth keeping.

Tell her your going away for the weekend. Get a hotel room rent or borrow a friends car. And follow her movements over the weekend. Sounds funny but it worked for a friend of mine. But if you feel you vcan't trust someone move on don't do this to yourself if she wants you she will ask you to come back.