Originally Posted by redpepper
I would suggest that in the case you are talking about DD123, you had your feelings hurt and perhaps she could of approached it differently. She was excited about it and didn't tell you she was going to? This didn't just come up, it was arranged and she didn't tell you it sounds like. She didn't tell you, by the sounds of it, because she thought you might object to her having a threesome. That to me is not responsible. Poly to me is based in responsible non-monogamy, it has it's roots there. Use the poly term as you will to feeling loving in casual sex, but being irresponsible is just plain irresponsible and perhaps why she feels like a slut in a negative sense. She chose to avoid being honest...
I think it could be the opposite phenomenon at work. Perhaps the DD123's girlfriend thought it would be no big deal to him if the ex's girlfriend joined them. It is also possible that DD123's girlfriend didn't tell him because he might have said "ok" but underneath she felt like she "should" be having a threesome with DD123 and a third person, instead of being the "third" person with two other people.
Keep in mind that I do not necessarily "believe" either of these scenarios. I'm just putting different spins on the situation.
DD123, you should get your girlfriend over here so the rest of us have her perspective on all this.