Be honest about it.
There's a friend I have I was jealous of because she was moving into assistant management position at a job we shared. I was going to be leaving the company soon and already had a new job, and I really had no reason to be jealous. I should be happy for my friend that she was moved into such a position. I knew feeling jealous or being jealous was wrong, but I still felt it. I revealed it to her and let her know that I didn't want to feel that way, but I did, and that I should be happy for her. She brought sympathy toward me, even though it wasn't necessary. But I do feel it helped heal the process, as it is no longer an issue for me. It was a way for me to be open before her, real, and honest.