<human>: Can you give me a shortened version of the text?

Hello relationships. My current girlfriend and I have been together for about a year now and we are both well aware of our pasts. Nothing crazy, but past relationships, sexual relationships, and we aired somethings out early on to make sure we were okay with our pasts. I always stood by and have that past won't matter to me and it's good we told each everything.  And that we will always will tell each other and not keep anything from each other. However, recently I have learned that a friend she is often with and hanging out with have a sexual past. This was purposely kept from me and when I asked I was met with anger and the conversation was turned out to make me into the bad person for even asking. The reasoning being is that she said I didn't need to know and it didn't matter since it's insignificant. She had said her friends said that she didn't need to tell me for my own protection. I found this to be incredibly inconsiderate that she would listen to her friends and purposely keep me in the dark. Now I'm worried there are more things she could be keeping from me or will in the future as well.
<bot>: Significant other purposely kept information from me about a person she often sees and hangs out with and I am left hurt. Is this worth leaving over?