<human>: A bit of background. I met my girlfriend online 
and so the first 3 months of us dating were 
purely online. I thought that we were fairly serious and we talked a lot on skype.We started dating in January and 
in February she went to Jacksonville and stayed
in a hotel. She went to Jacksonville because her best friends' boyfriend lived there (Navy). Coincidentally, my girlfriend's ex also lived nearby. At the time I knew she would be seeing him and they ended up smoking weed and drinking, although she said they did nothing else... 

Fast forward to now, she moved in with me about 5-6 months ago. I found a picture on her shoebox(app) in which some guy had a his hand on her leg. After asking her she again insisted it was nothing... Soon after she broke the news that she had hooked up with him once while she was there... I don't know how to feel. I just feel hurt and betrayed. She says that this was before we met and she never thought she would love me as much as she did now, that is, she insists that me and her weren't serious back then... 

How should I deal with this? Is the cheating lessened considering she hadn't met me in person yet?

Provide a brief overview of the text.
<bot>: girlfriend cheated on me many months ago when she thinks we weren't serious and now I'm struggling with what to think and how to continue