She has mentioned it before herself, after watching a "movie", but alcohol was involved..
In my life time I have had two girlfriends who were into threesomes and even organised them for me.
Why the fuck I didn't marry them is beyond me
I mentioned the topic a few days later, sober, but she wasn't keen..
If it aint broke, you can't just throw it out now, can you? these things aren't cheap!
Me & my wife have done it 5 times