Pushing the Limits. A Very Open Arrangement, #3

Our marriage was no longer monogamous. Suzy's antics at a student house party had put paid to that, and a few weeks later she'd followed it up by offering herself in a free-use arrangement to my ex-army buddies. I'd been so caught in the hedonistic thrill that I didn't consider the long-term consequences. The next step was for me to become more involved, and we sought out like-minded couples for swinging dates.
Everything was hunky dory, so a week-long stay at a couples' resort in Mexico sounded like the perfect vacation. Things couldn't have started better. Our very first hook-up resulted in Suzy getting exactly what she likes every which way from a stud called Dean, while I connected with his beautiful partner, Cyndi. Before long though, I became a little uncomfortable with Suzy's care-free approach to hook-ups.
She randomly overstepped boundaries, and her competitive nature with a hotwife called Daisy pushed the limits even further. Suzy and I had changed. We were no longer the same people we'd been six months ago. I knew we'd never get our old selves back, but I suspected that bothered me more than it would bother my wife. And why couldn't I get Cyndi out of my head.?