My boyfriend acts like he's so innocent says "i know how it feels i would never cheat on you or anyone for that matter". There is one girl.. his ex.. who is a slut and a *****! who also is my ex best friend.. who stole him from me two years ago. Now, him and i have been together for 11 months. This girl cannot leave our relationship, she "has her ways". From a very reliable source i heard they hook up. Of course when i asked him about it he denies it and brings up my mistakes..
i dont not know what to do at this point she gets under my skin like no other.. please HELP! and if you have a similar story (with an ending) please share :)

Saying things like that, 9 times out of 10, is a good indication of there being cheating afoot.