Swapping up

My MIL lost her husband several years back now, very sad. My wife was devastated. However, not long after MIL Martha hooked up with a close friend and nice guy we knew. After getting to know him he wasn’t as nice as we originally thought.
Fast forward, it has been several years and we decided to get to know MIL’s Dave better since they’re still together. They never got married but it wasn’t obvious what she saw in him. Thank goodness for backyard pools and cookouts! We invited them over for an afternoon / evening to relax, unwind, meal, and whatever. Little did we know~
After some pool time, good food and plenty of drinks we hit the pool again. By then it was dusk and atmosphere very sexy and playful.
My wife said to me “I know what it is, look at the fucking cock on him”. It was hard not to notice the massive bulge in his trunks. Once we were all on the water again my wife couldn’t hold back and told her mom what she observed. That was it. Martha didn’t deny he was huge. With that she asked Dave to join them/us at pool side and told her daughter she should try it!! WTF, I almost choked on my drink. And so it began. She pulled Dave’s trunks off and started jerking him. I pulled my shorts off to compare cocks. I was 8” uncut and thick. Dave was 10”+, cut, with huge girth. All suits flew off, my wife grabbed Dave’s cock, Martha grabbed my cock and stated sucking it. MIL’s tits are huge 40D saggy melons and wife’s are bigger. We all had amazing sex in the pool with each other. Wife sucked and fucked the biggest cock either of us had seen as I fucked her mother in front of her. It was an awakening and most erotic. It has been 3 years now and we continue to get together as often as possible ~

I had permission from my ex wife to have her mother, always remember her commenting after first time I fucked her mom, wanting to know details, turned her on improved our sex life dramatically