It started in lockdown

Back in the 2020 lockdown I than 25 started fucking my sister than 22 as we were bored and nothing else to do, that wasn't boring from being repeated over and over again. Of course we got careless, and my sister got pregnant. So, no hiding it from my mother divorced and her mother widow of 13 years at the time, father's parents were departed years earlier and our father didn't take Covid seriously and so it took him. Not really needing to work to get by as we were well-off financially. I was a little surprised how well my mother than 43 took the knew I'd gotten my sister pregnant. We were alone as our mother was staying with her mother than 61 so she wouldn't be alone. Once the realization was accepted, planning for what we would do started. My sister was quite willing to act as my wife as was suggested by our grandmother. Finally, our mother also accepted it as the best option as all tests showed the baby to be healthy. But as the pregnancy progressed after the lockdown was finished and us all living together, my mother and grandmother both decided we should make a foursome arrangement. My sister was in full agreement, and I liked sex and that is how it is now I'm fucking my sister who is pregnant with our third. Tests like all others she had for our other two children show no problems, soon she will stop intercourse between us, and I'll be just fucking my mother mostly and about once a week my grandmother. We sold up and moved interstate as we were too widely known in our previous home state as siblings.