Men : Do you mind if your wife/girlfriend enjoys anal sex with someone else? Ladies : Do you mind if your man if enjoying anal sex with someone else?
As long as he's enjoying himself, my husband can have any kind of sex he wants with anyone he pleases. If he'd enjoy being on the receiving end of anal, that would also be OK.
Do's: Set a VERY specific set of rules. Understand that people and emotions change, so therefore, the rules are subject to change with mutual agreement. Don'ts: Don't violate those rules.
I believe for this to work a couple needs to have been together for a long time, be very committed and in love, and they both have to agree to it.
I've been in an open relationship where we could date other people, as well as a swinging relationship where we play together (ie, same location). the first one didn't work out, but the second one is still an amazing success. Playing together makes a huge difference!