My girlfriend told me in great detail how she had sex with a famous music star; not sure how to feel about it.

She told me how they were in the car and that they were kissing and she sucked him off. She could see I was getting agitated by it so she tried to defend herself a bit by saying his cock looked exactly like mine.

I feel pretty pissed off but dreams are dreams right? Or anyone with knowledge of dreams meaning; could this progress to future problems such as cheating?