<human>: Can you summarize the given text in a few sentences?

My girlfriend [21F] and I [21M] have been going strong for 8 months. We had to do long distance in the summer because of school (university) and over the summer she cheated on me with a past friend when she went to visit him. 

I tried not to bring it up even though it made me uncomfortable but I finally told her that I wasn't comfortable. She told me nothing would happen and that was the end of it. 

A month later, I see that they are sexting and that they hooked up and had sex when she stayed with him. I was heart broken and she apologized. 

My problem is not only that she cheated, but that she didn't come clean about it and lied to me for so long AND continued to talk to him. She went to see him knowing that they would have sex and then continued to do so for the duration of her visit (over a week). 

It's a pretty exclusive event, she knew the guy and had a history with him before he transferred from our school and knew she would never get a chance to be with him - this being the only time she could ever get to have sex. Should I work towards forgiveness since I don't think she would ever do it again and try to still have a relationship or should I just forget about her and try to move on with my life?
<bot>: girlfriend cheated with another man, not sure if I should continue seeing her even though I don't suspect it ever happening again