Thank you to everyone who replied. Great food for thought.
First things first. Divorce is not on the cards for me, there are far too many factors at play the main one being ill health (hers). So I will leave it at that.
I have decided not to volunteer at that place again, I'm a serial volunteer so I'm quite good at finding community initiatives I find interesting and fulfilling.
The one thing I did, was to analyse this with a cynical hat on, doing that things don't look pretty - so I was trying to ignore it. But I think it needs to be said.
So this is my analysis being completely cynical. Up until I went to her party all our interactions were on neutral ground. The reason I said her party made me realise she wasn't ready to become an adulterer is because her thing is to have groupies. The party was her place where she was in control and shining with all the attention she was getting. Due to her job she has a number of devoted followers. From talking to her (we talked a lot) she is in a stale marriage, so I realised that getting people to fawn over her (both men and women) is her way of finding whatever she perceives is missing from her life. Where I look for emotional connection and sex she looks for attention. I also realised that all of the "moments" we had from the beginning were initiated by her. So, being completely cynical, she could have been grooming me to be another of her groupies. Problem is... I'm far too much of a predator (in the nicest possible way) to be a groupie. Yes, cynically thinking, she could be as much a predator as I am.
I don't think she is doing this consciously, of course. She's just very sociable, incredibly likeable person, and from a male point of view she's sexy as hell. She's not British, she comes from a country where women are typically thought of a sexy and sensual - and by god she lives up to that; although most of her groupies are women (trying to emulate her but failing.)
As I said I decided to move on from volunteering at that place, however, I need to give it one last go with her. I need to know whether my cynical mind is right or my emotional mind is right in hoping there's still a spark.
I invited her for a night out, she accepted. So, that will be a decider.
Thank you so much for 'listening' and your comments. It did help me put things out and read your opinions.