In 2004 I met “B”. She was my boss in a team in the firm where I worked. She was engaged to someone I knew “M“, but we became close emotionally, not physically. My own marriage didn’t feel too good (I later found out my wife was having an affair). She is a very petite and well-spoken woman and we got on very well. We had a ‘thing’ between us. During our thing she would often criticise her fiancee in front of me, but we were careful because of office politics. Our ‘thing’ lasted some time until she decided to quit her role. At her leaving party in a local pub, our colleagues asked her, jokingly, to describe her “perfect man”. She had had a drink (or three) and described me to all my colleagues, who all turned to me staggered. The next moment her fiancee turned up to collect her. Our parting was quite tearful (we were both very emotional).
I left the job in 2009. I saw her again in 2011 at the shop where I had taken a job (My wife and I reconciled, she was promoted in her job, and we had a child). “B” had married “M“, and had 2 children. She told me she was on Facebook, so I became involved too. We kept loosely in touch. In late 2017 I got a job in a Financial Services firm. On my first day, I bumped into her now husband “M“. The first thing he said was “B****’s here too!” which really surprised me, but not that day; she was at home with their children. However, the next day, she turned up and came to see me, happy to see me again. So, we sort of started up again. I noticed too that he was very friendly with another, younger woman, working with him on his team. There were times when “B” could be seen going to talk to him, or just checking up on him (I think). I’m sure I wasn’t seeing things, but I started to become friends again with the couple.
In November 2018 “M” told me he was going to another firm but the job was not fixed. “B” was “annoyed” according to him. I saw them together a few times, but he took the other woman (his colleague) to lunch rather more than “B” that I saw. At his leaving party at a local pub, we were already there when “B” turned up. She greeted him, then I noticed she kept looking in my direction until she got a chance to sit right next to me. It was fantastic. Nothing happened, but she suddenly was talking and talking, and relaxing, drinking wine and buying me Cokes (I was driving), and constantly keeping her body position toward me even when talking to others. I found out she was only three years younger than me (47). At one point she grabbed my phone and found pictures of my wife and daughter asking lots of questions about them, and being quite amazed at how long I had known my wife (30 years!).
We started to meet up more often in the office. She bought me a special “you know me so well” card and gift for my Birthday in November. At the firm’s Christmas party she did a lot of networking whilst I relaxed, although we talked a fair bit, but I reckon she realised I didn’t mind (the way couples do at parties because I know her attitude toward such events). On Christmas Eve, we bought our children to work, and “B” put herself out to bring her children over to where I was with my daughter to say hello and make a fuss of us all meeting up. We carried on.
Then another colleague left the firm, and we had a leaving party in a pub. “M”, her husband arrived. I was happy to see him and we caught up. “B” came up in conversation. He hinted at a jokey discord. That she and he were not getting on. He had “escaped” that evening. There was banter. However, he had sat right next to the woman from his former team at our office and she was very giggly and laughing at everything he said. Basically he gave a hint that I should take his place with “B”. I then found out that he’s 6 years younger than her, which was a surprise because I thought they were both younger than me. I also found out that she is a Catholic (I am Protestant) which also explains a few things. However, I still feel the same way for her, as I did when we first met. Whether she feels the same way about me, I don’t know, but I think she does but is bound not to say.
From what you have said it does sound like she has romantic feelings towards you. I think it best if you try to stay away from her (in all capacities) if you value your marriage. You are both married with kids so it is a dangerous slippery slope to become "close friends" with someone when clearly the feelings run deeper than friends. It could all end in tears. So I think you need to ask yourself what you want to do about your own marriage? If you value it - stay away from Mrs B flirtypants.
Are you married? You don't mention your wife at all or where she fits into this entire scene.
Be careful about letting anything more to develop with your "office wife." You had feelings for her years ago - she is not the same person and neither are you now.
Their marriage MAY seem rocky. The husband is out of line if he is giving you "hints" for you to advance on his wife.