Work Place Romance

I have been working in my current office job for 2 years now and always had a bit of closer relationship with a women in the office.
We are both around 30, married and not the type to ever consider cheating.
About two months ago we started emailing each other a lot during the day (up to 20 times) and some of the comments were flirty on both sides but nothing sexual. It was more general chat about our lives.
About 3 weeks ago she cut all ties in our emails and blanked me In the office which upset me because we were good friends. We eventually had a chat about it and after reading up, we were ticking all the boxes of an emotional affair. We both panicked a little at this but laughed off the emails in hindsight and back to being chatty.
At an after work officer gathering, we chatted for about an hour and she was very flirty with me despite our previous discussions and I joined in. We arranged to go for lunch this week but next morning she cancelled by text and has gone all ignorant again from no where.
She then started talking about other guys in the office totally randomly (make me jealous, throwing me off the scent?) which had never been mentioned before. We have both admitted that if we had met ten years ago we might have gone out but happy with how our lives turned out. At present we are barely chatting.

I cant stop thinking about her now and I am even struggling to sleep, mainly because she is so nice then distance. If I am being honest I don’t know what is going on. Any advice on what is happening would be great and why she is being like this…