My boss's wife

I'm Burt 23 and work for Brian 71 who owns a landscape business, I'm his general dog's body and get sent to do the minor jobs that come in from time to time. He likes the big jobs and they keep him busy with the rest of his employees. So last March he got a call from his wife Margret 58 about redoing their garden and I was sent with the instructions to do anything his wife wanted done. At first it was installing large rocks for a rockery and replacing old garden bed borders. Then top dressing the lawn, finally she wanted her garden shed cleaned out and made fit for purpose (her words). There were 2 bench in the shed (a old single car garage), one lower in height than the other she used for potting up large pot plants. I had finished the clean up and put everything in its place. When she entered and told me I had one more job to do, I enquired what and was shocked as she said it was her. She wanted fucking by me and I'm do fairly well with women myself and really liked sex. So I decided to do as requested and fucked her. I soon found out she really liked being fucked and was called back next day to finish up the work. I thought it was all finished the day before, but done as I was told and found out, Margret wanted more sex. We fucked the whole day and I said Brian might not like me coming all the time. especially as anyone can see the garden is finished. Margret answered so what, he can't get it up anymore and so he has sent you to keep me satisfied. I had a doubting look on my face or something and she rang Brian and told him she wanted me to keep coming over to fuck her and I heard him say as long as you want darling he's yours. I'm still fucking her at least 3 days a week and have also met her on the weekend for sex. But I wasn't going to get paid for it I was told by her before I agreed to see her. I agreed thinking if I refused she might want someone else and I really like the sex with and the easier pace of my work life now. So I'm willing anytime day or night, I do have a girlfriend Wendy 22 a nurse and as she works shifts, I available at night for Margret and Margret doesn't want to intrude on my personal life. So we have a great relationship.