I wouldn't advise it.

I've had plenty of friends that were swingers or in open marriages and all of them are broken up or divorced now. I'm not saying it doesn't work for everyone, I've just never seen it work out.

Part of the reason is that there's this funny little hormone called oxytocin that likes to take over. It helps create that monogamous bond and is dumped heavily during sex. Throw in phone calls from boyfriends/girlfriends while you two are at dinner, emails about next time and so on and it doesn't take long for it to all go kaputniksky.