Unemployed and roped in

i was unemployed and being supported by my parents, I'm the middle child of 3 and the only one not to go onto university. I was sent to look after my father's mother Grace who lived outside of the next town over from our town on 12 acres, Grandpa Paul had died, and my father decided I should go and help my grandma. At least I wouldn't be under his view all the time, I would still get money from him. Grace of course was happy to see me and didn't berate like my father for being unemployed. Helping my grandma was good and I was able go into the town for fun. No luck finding girlfriend, but I liked being with my grandma. I also got short-term employment at times, which added to my money supply. After a couple months Grace caught me masturbating in the bathroom, she undressed and joined me in the shower and took over stroking my cock. I was little shocked at first it passed quickly, and I started feeling her up. Then I mounted her in the shower and fucked her. After we finished in the shower, we dried each other, and I asked her for another fuck and we went to her bed and fucked again. We were just getting out of her bed when my parents arrived, Grace had already dressed and was just starting to dress. Grace went to meet my parents and had them in the kitchen when I appeared. My asked was I just getting up for the day and Grace told him I had been working hard for her and had just showered after getting dirty. Not game to press his rebuke of me in full of his mother, he stopped. After a couple of hours, they left. Grace sat looking at me and I asked her was she up for more sex and we returned to her bed. We regularly fuck and Grace is a very willing lover. My father thinks I'm a loser.