Bumped into an old flame at the weekend, she seemed pleased to see me and introduced me to her friend/boy friend, I'm not sure which, with fondness or so it seemed.

It was a real shock to see her and I didn't really say much, in fact I was a little cold. I left the club shortly after as I realised that my coldness was a ploy by myself to hide the fact that I still think of her fondly. We had been split up for about six years now and although there had been times that it looked like we may reconcile our relationship during those years, it never happened and concequently this is the first time I have seen her in two years.

I thought that I was in a really good place about all this but meeting her has kind of put me back a step or two and I wonder why fate had us meet this weekend?

Any help would be gratefully received

Yeah, that unexpected "punch to the heart" can catch us all out from time to time.
Since the meeting was by chance try not to read too much into it. Can we assume you have had other relationships since splitting with her? Unless you have lived the life of an Anchorite and carried a torch for her all this time, I think you have to put this down to a memory rekindled by chance.
You don't know the status of the friend/boyfriend so it would be foolish to try and relive past pleasures.
If you really need to exorcise this spend time at the same club and see if she appears again, if she does you can ask the magic question "So, tell me what you are doing in your life now?"

HI,
I am not a Psychic. But, have you considered that it might be "fate"? That you two just happened to be at the same place at the same time?
If it's been two years, and your life is going the way you want it to, I wouldn't be too concerned about it. She was probably just being nice. There are many people like that; no hard feelings toward anyone.
Personally, I would get on with my life, meeting new people. I do wish you the very best of luck.