Well said manI don't see a whole lot of regret here ... I think some of the initial regret may come from violating the wedding vows, which most of us get drilled into us. But the older you get, the less important those become. There's a lot of cheating going on; the only difference is swingers are open about it. Most people aren't.
BTW, I don't consider swinging/open marriages/polyamory to be cheating. Cheating happens when people are not being honest. IMO if everyone is upfront, it's not cheating.