Sharing Our Innermost Thoughts

Something has upset my friend and made her feel very sad. She said that she rather not talk about it. I told her that is completly up to her and if she wants to she can come to me and tell me what is going on.
She did not tell me but told another friend. They told me that she will tell me what is going on later but that there are reasons why she only told them only.

Although I know it’s stupid I can’t help but feel jealous that she did not tell me but them. What I actually should be concerned about is that there is something that made her sad.