Let me be more clear.
There are no "rules"! You can NOT expect to have a happy, fulfilling relationship with anyone playing by rules. Why not? Because, the two of you are not playing by the same rules. There are always some inferred laws that apply to both parties.
For example: in every relationship I've ever had, although it was never stated in this manner, it was understood that neither one of us were allowed to put any genitalia in or adjacent to our bodies.
However, this summer, I had a non-exclusive arrangement with a bisexual girl (might have benn an experimenting hetero - who can really say? Not sure she knew herself) who thought this was fine, as long as the other party was there to either participate or watch.
You asked if it was against any rule. I told you it was.
Here's what you have:
You have a girl that you care about.
She wants to break bread with an old "friend".
She has a history of infidelity.
Understand this: A woman's needs can not be summed up specifically, as each woman's needs are different. In most younger girls, even they don't know what they want. So, there's no possible way for us to determine if all of her needs are being fulfilled.
What makes a girl cheat? Nothing "makes" her cheat. She makes a conscious choice to start a relationship with someone else, be it physical and short term or romantic and long term or what have you. Most younger girls that cheat do this becuase it was done to them and they want pay back. Others just can't believe how unbelievably obtuse most men are. They practically spill it out, how bored they are with the curent situation. These are attention wh*res and drama queens. They do it for the excitement. Let's face it, it feels good physically.
Some men on the site might say if they KNEW she wasn't going to cheat that it is still not a good idea to let her go.
Each of us are different.
Suppose you tell her that your concerns. You are going to sound like a control freak or a chump, either way she hears it.
One of the DJ's here that has been screwed over a time or two, would shout out the word NEXT, just to save himself the pain. If you like her, it's going to hurt anyway.
What are you going to do, when you tell her not to go and she says that it's just dinner and you're not her father and she can go if she damn well pleases?
If I were in your shoes, I'd call up one of my old girl friends from high school and have a double date.
