Older Neighbor Wanted A Cold Fuck

In my early 20s, I got my first full-time job and apartment in a new city. I hadn't dated much, but got an unexpected opportunity when I ran into a neighbor in the floor above me while we were both getting our mail. Shirley was about 50, slightly large with curly brown hair, and wearing just a light gown. We had seen each other before but never talked. On this occasion she was very forward but not verbose, more just direct and curt but kept asking short questions or giving short answers to me as she asked about my work and life here. I thought I had seen her with a man before, she explained that her husband was often away a lot. After just a couple minutes she said she wanted to go back up but invited me for some coffee, which I accepted out of curiosity.

Once inside her place she was soon even more direct, explaining that she was a bit mad before her husband was cheating on her with a younger woman. She actually said she understood it, but thought it was unfair that he lied about it and didn't give her permission to do the same. She asked if I thought that was fair, and I agreed it was not. Before long she sat back with her legs apart, revealing her hairy pussy to my sight, and saying that she should just be able to fuck any willing young man herself. It was obvious she was selecting me, though perhaps just because I was available rather than for anything special about me. Still, my dick responded so I was thinking of taking her up, and when I slightly hesitated she asked if I was a virgin. I wasn't, but said I had only had sex a few times, and didn't have a steady girlfriend. She then basically said here's my chance, and that she was past menopause so she was very safe. She then sat up on a desk, her open pussy facing me. I stood up and unzipped to expose my hard cock, which she never looked at, instead she just stared at me expectantly. I fumbled my way into her pussy, which was plenty wet, and started fucking into her. What I most remember from this is how weird it was that she didn't show any signs of pleasure, she just kept looking at me, or sometimes past me, as I pumped into her body. I asked if she was enjoying this and she just said to keep at it, "you know what to do." I felt for a while like a slave to my dick, that she was probably judging me like her husband as a horny man who couldn't be trusted but was just using me for revenge. And of course I was using her, really just sort of masturbating my cock with her vagina like she was some kind of big fuck-doll. I got close to cumming and she just stared at me as I got more excited and finally started to ejaculate into her. I felt embarrassed afterwards and she did nothing to reassure me, just telling me I could clean up in the bathroom and hinting that I should leave, which I soon did. We never did this again and I only saw her a few more times, when she basically just spoke very neutrally as if we had never done this. I saw her husband once again and hope he never found out what we had done. I still don't know if I should regret this or not, but can't say I wouldn't do it again if I had the chance.