What do you say if your girl hints that she wants to have an open relationship?  maybe she has someone in mind already?

Yeah, it's definitely an odd request, if he/she is asking, then the chances are, they aren't sexually satisfied.

But hey, some couples have reported success from participating in an open relationship - who knows, I guess it depends on the type of relationship and the scenario.

Personally for me, if my husband brought that up I think I'd have to ask some serious questions about why. It's not a situation where I would feel comfortable sticking around - for me, commitment to one person only is the only thing I'm okay with. Open relationships may work for some people, but I'm not that person.

Ultimately, you'd need to decide whether or not it's something you're okay with.

No way dude  .  As with @Jasonn, disease and true love is a problem.  Also, as with @Jasonn, I would only do that with temporary women.