The Long Walk

I'm a widower 62 and am retired, I live alone and all my children are grown and have families of their own. I like to go for walks in the late afternoon and have walked as far as 10miles at times. As I walk I sometime see young couples cuddling and such things. Last May my sister Robyn 59 came for a visit, she is the youngest of my siblings. She is divorced and her family is all grown up and left home. Robyn started come for walks with me. Nothing special in that, on the third day of walking the forest track together. We came upon a young couple having sex a few meters of the track, they were really going at it and didn't see us. We continue our walk, talking about what we had just seen. We came to a fork in the trail, where the old track went down a hollow and across a stream. But wasn't used much now, since the new track was built as the new track led to a new better lookout. We had been to the lookout twice before, so we went down the old track for change. Crossing the stream we came to the old lookout, it was a bit overgrown with plants. The large rock people used to sit on looking at the view still had a view to look at, so sat we sat down and looked at the view. We were still talking about the what we had seen, then Karen said she missed having sex since her divorced. She asked me If I missed sex also, I replied I did. Then said Well we're alone here, why not satisfy each other. I was taken aback by this and answered We're Brother and Sister. So what she said I'm too old to get pregnant and it will a secret between us. Nobody will know except us. She started to undress and I was still hesitant, but then thought this might be the last fuck I could ever get. So I started to undress as well, I gave her a kiss and then she went down on me and we ended up having a 69 and then I fucked her. After we finished we dressed and return to my place and we slept together that night. Each day we went for a walk and returned to the old lookout and had sex. After 2 weeks Karen returned home, soon after getting home she rang me and said she was thinking of selling her place and wanted to know if she could live with me. As she was masturbating thinking of me every night since left. I said I would like that and so she sold her home and came to live me in late July. We sleep together every night and have sex regularly. We act like a married couple, nobody in the family knows were sleeping together. They think we're keeping each company in our old age.