Older married woman

I was 20 and in the 2nd year of uni I moved out of halls of residence and rented a flat with a mate. But he never paid his half of the rent so we fell out and he moved out. So I thought ok now I gave 2 rooms. But within a week this mature student who I knew came up to.me and asked if she could rent that room. She was spending 3 hours a day traveling to and from uni and her marital home. And it was tiring and causing some friction between her and her husband. I said yeah that's fine. She would go back home at the weekends. And for the rest of the term that's how it was. We became good friends and in the evenings I was out in the student union bar and she stayed in the flat or I found out later was seeing another mature student who lived in town and also married.
Come the summer break we sublet the flat and she went back to hubby and kids and I went back to my parents. But I had agreed to housesit for her when she and her family went on holiday for 2 weeks. Her kids were teenagers 2 girls and a boy.
Back in the autumn we returned to the flat and continued as before.
But in December things changed. It was a bitterly cold night and I woke needing to go for a pee. Which was an effort because the shared bathroom was 2 flights of stairs down. Anyway I could hear quiet sobbing from the other room. So i thought I'd better see if everything is OK. If she's still sobbing when I get back from the bathroom I'll knock on her door.
Went the bathroom and listened .no sound. I thought ok that's good. But I thought I'd better check anyway. I knocked on the door and went in. She was awake I could see in the moonlight. I said I thought I heard you sobbing. She said no but thank you for checking on me. We got talking anyway. I sat on the edge of her bed. Thank god I was wearing my dressing gown. She sat up in the bed. She had a nightie on and I could see the shape of her breasts. One big and one slightly smaller. My cock stirred under my dressing gown but I managed to disguise it. We talked for a long time about all sorts of things. At some point she put her hand on mine and said God you're freezing. Why don't you get under the covers. I couldn't believe it. And at this point I have to admit I was still a virgin so to be allowed to be the same bed as a gorgeous woman who had obviously had a lot of sex was mind blowing. I tried to keep apart from her but it was a single bed. We talked a little more then fell silent. Then I think she said did I want to gave sex. God did I? I took off my dressing gown and my pants. My cock bolt upright. She started wanking me. I really had to hold back. I didn't want to cum too soon. I asked her if I could see her body. She knelt up and took off her nightie. Yes petite white mummy body. She let me finger her and of course i was too rough. She said don't worry about me i don't orgasm anyway. I thought that was a shame. I let her carry on wanking me for like hours. I wasn't sure if she let into her pussy but eventually i moved and got between her legs and sliding my cock into her married pussy. Off course I couldn't last that long and I filled her pussy with streams of hot young cum.