<human>: Can you condense the text into three sentences or less?

The short version, is I found out that my girlfriend of 6 months cheated on me with a guy she had previously had sex with, before we met.  She claims all she did was make out twice, but I know for a fact it took place in her bedroom, and this is the type of girl who doesn't have a problem giving up the goods.  So I have this doubt that all she did was make out.  

This just happened yesterday, me confronting her about it that is, and I left saying I need to think about things.  I decided to break up with her, am going to tell her today, but I haven't decided if I should forgive her.  

There are so many more things that I would need to forgive her for, not just the act of cheating.  What do you all think?  I feel that to forgive someone, then they have to be truly sorry.  And I have a hard time believing that she is.  I think she is only sorry for getting caught, not sorry for hurting me in the way she did.

What are your thoughts on this?  Anyone else been in a similar situation?
<bot>: Girlfriend cheated on me, and I plan to break up with her later today.  Yet should I forgive her for what she did?