This is something I don't quite know how I got into, but do know it isn't going to be easy to end.

Several months before my mother in law was supposed to be going to die, my wife asked me if I'd fulfill a wish for her mother. I basically moved into her home for a couple of months during the week days and fucked the shit out of her, night after night, after night.

The sex was amazing and my mother in law had me doing things with her, I'd never thought of, or tried before. My wife on the days I spent at home (Mostly weekends), wanted to know some of the details of the sex I had with her mum, how we fucked (Positions) and if her mom was enjoying herself. But not the sordid dirty things I did with and to her mum on her request.

The final time I fucked my mother in law before her longish hospital stay, was actually in hospital, or should I say in the hospital grounds. It was summer time and we had sex behind a temporary screening unit close to her ward. She sucked on my dick for some time before having me fuck her arsehole until I made her orgasm and I came filling her rear hole.

My wife knew when we returned I'd fucked her mum, but only said "Thank you".
My mother in law, somehow made a full recovery. Not just a reprieve, but a full, you're perfectly healthy recovery and I and my wife were totally shocked.

It left us with a dilemma of course. With my mother in laws demise, it would have been forgotten about and everything would have returned to some kind of normality. With the forty nine year old, who by the way is a very attractive forty nine year old, being healthy and invigorated, she asked me if I'd consider keeping our arrangement going. I asked her why she didn't want to find another man to fulfill her very sexual needs. It was then she showed me a series of texts between her and my wife.

The texts explained how my wife was finding it hard to keep up with my sexual appetite, and that she didn't want to lose me. The health scare was true, as was the treatment and complete recovery. Yet I still had a nagging feeling about how it all just happened the way it did. I also knew deep down my wife wasn't able to fully satisfy me sexually, after having sex with her mum.

I should have said no that morning and spoken to my wife. But instead I spent the whole morning fucking my mother in law and loving every horny second of it. Cumming up her arsehole, the third time I'd cum inside of her that morning, I knew she was a far better lover than her daughter would ever be.

Back at home when my wife got in from work, I didn't get to say anything before my wife said "Twice a week". Nothing more and not a mention that she knew I'd been fucking her mum all morning.

And twice a week it has now been over the last year. My mother in law is insatiable sexually. We often fuck for hours and it never ever gets boring. I'd go as far as to say, I'd be better off living and fucking my wife's mum than I would be living with her. And that's really why I'm confessing. My mother in law has suggested just that recently.
And what's more, my wife actually the same day her mum mentioned it, said "You and mum are so close these days, we should all live together don't you think".

It's not what my mother in law was thinking I'm sure, but it's a compromise I'm not too sure will work. But then who knows...