My Wife's Sister.

I'm George 58 married to Ruth 56 and have 3 children, 4 grandchildren. I live with Ruth in a small town in a 2 bedroom cottage. We downsized after our youngest left home. Late 2017 Robert died he was Beryl's husband, Beryl is Ruth's twin sister. Robert died in a car accident just after is business went bust. His insurance and the sale of their home and other assets just paid off their debts. Beryl was very distressed by the happenings and we asked her to stay with us. Ruth and Beryl are mirror images of each other, but Beryl isn't as bright as Ruth. She had it soft since she married Robert when she was 18, Ruth had to work to help get us where we are today. Beryl only had one child Paul who was spoilt rotten from birth and got into trouble, until they couldn't help him out of it anymore. He got 3 years and hung himself in his cell, he was 24. So with no family on Roberts side it was up to us to look after Beryl. Beryl had over the years alienated her other siblings, but Ruth wouldn't desert her sister. I had little time for Beryl, but I always trusted my wife's decisions. So Beryl moved in and after the rules of the house were laid out to her by Ruth, we settled down to life together. Ruth is a no nonsense type of person and Beryl knew if she didn't like it, she would have to leave. Ruth also liked routine and we lived by it, She would always let me have sex with on Friday or Saturday nights. Another night would be used if something stop our normal routine, all I have to do was tell Ruth I wanted sex in the morning for that night and it was booked in. It might sound weird, but it has worked for all these years. With Beryl in the house I couldn't walk around naked and feel up Ruth whenever I wanted to. This wasn't good for me, but Ruth knew I liked doing those things and she also enjoyed it. Try getting Beryl into activity outside on the nights we wanted to be alone. But it didn't work, then one day I was away out of town picking up fruit trees Ruth had bought. Ruth and Beryl were home alone and got to talking. Beryl told Ruth that she was missing sex with Robert and had started to masturbate regularly. Ruth was surprised at first, but started to question Beryl on what type of sex she missed the most. She found out that Beryl was into just about anything. Then she Beryl have you ever tried threesomes, Yes was the reply and I enjoyed a lot. So Ruth said How about you joining me and George for threesome sometime, I'm willing, but what about George she replied. Ruth said I think he will be okay with it. I got back with the trees and planted them. Ruth came out to the work shed and asked me if I would fuck her Sister Beryl. What is the catch I asked, No catch, I found out Beryl is horny and likes threesomes she replied. I'm okay with if you really want too I responded. Then you better rest up, for tonight your fucking us both she said and returned to the house. After dinner that night, as I wiped the dishes the ladies left the kitchen. Short time later I was called by Ruth to the bedroom, on entering I found both naked and their hair done the same way. At first I didn't know who was who, but then I saw the small scar on Ruth's shoulder and I knew was her. I asked Who wants to be first and Ruth motioned with her eyes for me to do Beryl. I got naked and the three of got on the bed and both me and Ruth worked on Beryl. After I have fucked Beryl, Ruth and Beryl worked on me till I really and Ruth mounted me. That was 10 months ago and we all sleep together every night since.