Isolation turns into fucking

Being in isolation with my sister Gwen 22 and cousin Jean 23, I was the lone male in the bedroom apartment. I'm David 28 single and it's my apartment, I purchased it 4 years ago and have almost paid it off. When Gwen and Jean came to the city to attend the local university, they moved in with me to save money and share the other room. It was going okay and once the pandemic started we were told to isolate ourselves and we did as instructed. But after a couple of days getting bored and unable to out. I was starting to get stir crazy and so was Gwen and Jean. Then one night I heard moans coming from their room and thinking they might be sick with the virus went to check on them and that when I found them making out. Both naked and in a 69 position licking each others pussies, I got an instant hard-on and asked them could I join them. Both were a little shocked at first, but then agreed to let me join in with them. I fucked both of them that night and have continued to fuck them regularly since. We all share my king size bed now and bath together regularly as well.