Found Explicit Video on Girlfriend's Computer

My girlfriend of a year recently had me work on her laptop, as she had been getting the "blue screen of death" frequently. I traced it down to driver conflicts, and fixed it.
However, while scanning trough the drives, I found a video of her having sex with two guys, while her best friend (another girl) watches. It was hidden in an obscure folder on her hard drive. The date of the video is from a couple of years ago. My girlfriend gives head to a guy on a couch while another takes her doggy. Both of the guys finish in and on her. Her friend sits undressed, fingering herself as she watches.
I would love to do something like that with her so should I mention I saw the video or just make it a suggestion one day and see how she reacts???