<human>: I'm a (m/22) and SO is (f/21,) We have been together for about a year & six months. We met at university and hit it off straight away, both of us would consider it be our first 'love' so to speak. 

She's living away at university, whilst I have graduated and I have a full-time job. The distance has hurt us quite a lot, as we have gone from seeing each other daily to seeing each other every two/three weeks.
We have also talked very seriously about a future together. 
She tells me over the phone how much she misses me etc and I feel the same. I visit her for the first time in over a month and she tells me that I she's kissed someone and spooned them too. This had happened when she was drunk and completely out of character. She cried uncontrollably for ages, apologised sincerely and understood if I would end relationship. She said that he made the advances on her, but feels like she has betrayed my trust significantly. 
I thought a lot about it, but I chose to stay with her because I still do trust her that nothing else had happened. As she has come home now for the holidays, we will see each other a lot more and I feel that things can go back to the same.

Condense the text into a few key points
<bot>: My girlfriend (f/21) kissed and spooned another guy and I've decided to stay with her, thoughts?