Grandma update

I'm Bert short for Bertram and my grandma Rose moved in with me after her home was bought by the government. I caught her masturbating and we started fucking and still are today. Except that my only sister Joyce 26 came to live with us due the ongoing pandemic and Joyce is bi-sexual and being in lockdown started sleeping with Rose to get herself off. Rose was also enjoying her relationship with Joyce, but still wanted my cock as well. With Rose encouraging her Joyce joined me in my bed and we started fucking each other ever since. Rose also joins in and we have regular threesomes, one problem came up. That wasn't foresaw and it was a power cut, we all decided to have a threesome. But with everything pitch black and unable to see faces. I was getting sucked off and was licking who I thought was Joyce vagina and nobody talking. I was getting close to blowing my load and got decided to blow inside Rose's cunt. Telling the sucker to mount my cock and she did as told. Just mounted me saying nothing, short time later I blew my load inside her. Usually this wouldn't have caused a problem, but Joyce was off the pill for a while and I wasn't allowed to cum inside her until she went back on the pill. Both shaved their pussies and I hadn't notice any different in the dark. Usually I we start with me licking Joyce vagina and Rose sucking my cock and then mounting me. But this night they changed their positions. No Reason they just started opposite to normal and after I had left my full load of sperm inside Joyce did she speak and I realized my mistake. After a short conversation we decided it was unlikely Joyce would get pregnant from one mistake. But of course you can get pregnant from just one fuck and Joyce is proof of that. Five months pregnant and all test show a healthy baby, just as well we don't approve of getting rid of babies. I've started looking forward to being a father, Joyce is very happy to be having a baby also. Only our parents aren't that frilled about the way their first grandchild was made, I wonder how they would react if they knew we were also sleeping with Rose and I was regularly fucking her.