<human>: So my GF of a year and a half and I (20 years old) are going through a break right now, and she has been really upset at me.  I deserve it completely, as I haven't been the best boyfriend recently, and I need to work on my mental health, etc.  I know her Mom quite well, and she really likes me.  After we began the break yesterday, my GF and I were both really upset of course, and I got an email from her Mom at some point during the day telling me that my GF doesn't know she emailed me and that she would like to talk.  I agreed and she is going to call at some point this evening.  

Should I tell my girlfriend about this before her Mom calls?  Am I betraying my GF's trust by not telling her that her Mom contacted me without her knowing? She could call any time, I would really appreciate your advice!! Thank you so much everyone!

Can you condense the text into three sentences or less?
<bot>: My GF's Mom wants to talk to me without my GF's knowledge.  Should I tell my GF before her Mom calls?  If I don't tell my girlfriend, am I betraying her trust?