<human>: My Gf and I have plans tomorrow and I ask if she would like to do something Saturday as well. She replied that she has plans with one of her other friends, Sarah. However, I was talking to a mutual friend of ours and she told me that she was actually going over to Marks place, her ex. Our friend told me that she didn't tell me because she knew id be jealous or mad. 

I am not sure what to make of this. I want to be mad but I cant. I see where she is coming from and wanting to protect my feelings. Should i take this as a sign to move on or a good sign that she wants to protect me and us together. Sarah told me that my gf said there are no feeling left between them they just go way back and enjoy each others company.

Can you condense the text into a few key points?
<bot>: my gf is going over to her exs place saturday and neglected to tell me. wondering how to process all this information. any one have a story of a similar instance or advice how to interpret this?