Widowed Sister Drains my balls

My sister Suzie 49 widowed 3 years ago and her 2 children grown and moved on with their own lives. Started coming to see me regularly as I lived nearby, I'm Davis 53 her only sibling and I'm divorced and likewise my 3 children have their lives and rarely visit. Suzie was lonely and unwilling to start dating again and then one she asked me if she could move in with me instead of her renting as her rent was going to increase. I said you can if you want, and she moved in a month later. She took over the housework and the cooking and it was like being married again. On her last wedding anniversary, she got very sad and started drinking heavily. That night she was drunk, and she went to bed and watched a bit of TV and then to my bed. Early next morning about 3am, she got into my bed and started kissing and fondling my cock. I asked the stupid question why you here, she said she wanted to be fucked. Adding I really need fucking, and my cock was already hard, and I hadn't had sex for a while and I had a willing woman, so I fucked her. In the morning (Sunday) I waited for her to wake and see how she reacted to me fucking her. She awoke and straight away asked for another fuck and ever since she has moved into my bed and drains my ball regularly.