Hi Vett
Im real new on here but I just read ur post and it stood out to me.
Your ex gf might not even be speaking the truth at the moment, she is just hurting still. Betrayal takes a lot out of a girl.
She wants you to feel bad.
But don't let it get you down, as long as you know how you feel and don't let what she says influence that. Of course she won't believe you if u betrayed her but in time she might come round. Shes hurting thats all, sometimes when people hurt they want the 1 who hurt them to hurt too - in this case thats you !!
Your not a bad person etc because of this, people make mistakes, and your only human (i assume :P hehe). Its all up to her really!
Look after yourself