My Spinster Sister

I'm Gregory 58 widower my wife Carol died late last 2020 heart failure, my children are all grown up. I have only a sister on my side of the family and she has never married or had any relationship with anyone. Carmel 55 lived in the city and decided on a sea change as she called it. Moved to the smaller town I lived in in May 2021, staying with me until she found her own place. I live in a 2 bed cottage which me and Carol got after the last of our 3 children moved out of the family home. Carmel is slim, short 5'5" and quite stacked is how I would call her breasts. Carmel is quiet around strangers, but not shy just reserved. After several weeks living with me I walked in on her getting out of the shower. She got a fright and and I got an eyeful and also a hard-on, it wasn't seen by her as I quickly retreated out of the bathroom. After that I started thinking of Carmel sexually and decided to try my luck as it were. I started giving her cuddles and not much more at first, but I was invited to wedding of an old friends son and asked Carmel to accompany me. She agreed and we had a great time at the wedding and Carmel enjoyed herself. It was a 40 mile drive home after and we had planned to just drive straight home, but it started raining and I decided we should book into the local motel. Carmel was okay with that and I could've gotten 2 rooms, but I decided to get one. Carmel didn't say anything and on entering the room, it had a single double/queen size bed. I waited for her to suggest getting another room, but she didn't. She went into bathroom and I stripped down to my shorts and singlet and got into bed. Carmel came out turned off the light and undressed down to her underwear. We went to sleep and later on I needed to pee and went the bathroom. Returning to the bed I got back into bed and Carmel woke up. Seeing it was me she just smiled and I decided to kiss her, she was a little shocked but didn't push me away. The kiss became a passionate kiss and she started to kiss me back and I started to feel her up and put my hand into her panties. She didn't try to stop me and I kept going and well she let fucked her. With us now lovers and still quite happy we cuddled up and went back to sleep. I wasn't her first lover, but was the first in many a year. As we were both still naked in the morning, I made a move on her waking up and she let me fuck her again. We had breakfast at the local diner and headed home. On arriving home I was feeling horny and decided to go for it again, she didn't respond straight away. But didn't say no either and after a little while we fucked again and ever since she sleeps with me. She isn't looking for her own place and has moved into my room, we have a regular sex life once or twice a week on average. Some people think we're married, my children don't know I'm fucking Carmel and probably think I'm passed it anyway. We aren't hurting anyone and are quite happy in our relationship and have no worries about Carmel getting pregnant.