Should I trust my girlfriend

I'm getting quite serious about my girlfriend and may be looking to take things to the next stage and live together. This weekend she casually admitted meeting with her last ex (6 years together). I admit I don't like the idea but leaving that aside it really upset me that she didn't mention this meeting. I'm not suggesting that she ask my permission or anything like that but I think she should have said something, particularly when I always let her know in advance if I have to meet my ex-wife or other female friend. her actions lead me to believe that she doesn't respect me or our relationship. I don't know if I trust her as completely as I did before, What would you advise?

There's nothing wrong with meeting an ex, as long as everything is out in the open. When your GF casually mentions it after meeting her ex, then you need to step back and look at her and her actions. A successful relationship needs constant communication but it also needs absolute honesty which develops solid trust. Follow your instinct and ask yourself why you don't feel comfortable with your GF's actions. You'll find your gut feeling with this issue is correct in every way.

I can see why you are upset. I would be very upset. She lied to you. No, she didn't mention this meeting so she was not being honest. If there was nothing to this, she would've likely told you. But she kept it hidden. why? You need to find out why.... Trust is VERY important in a relationship