Yes I have and in retrospect not proud of it.
Had a girlfriend when we were both in our early 20's. I liked her for the first couple of months but she really started to get on my nerves. She was very passive aggressive, snarky and was getting worse by the week. She had brought up in the past that she would be willing to try a 3-way if we could have one with a guy after trying one with a girl. I was not all that interested in either but certainly not a Devils Threeway so I passed on the offer.
Knowing that this relationship was going nowhere I re approached her about it. She was excited about it and was able to setup something with an old college friend of hers. We did it [it was OK but frankly not my cup of tea] and I broke it off with her less than a week later. She even asked if we could have a three-way with another friend of hers first? U'm no!
I was an asshole!