Don’t get me wrong, Jack, I always enjoy hearing what you have to say. You bring a fresh perspective to the discussion. 
Well, I tried this. It wasn’t just that “we can have sex with others”, it was more like that we could have multiple boy/girlfriends if we really wanted to. Or so we said…
We thought that if we weren’t so strict, there would be less chance of breaking up because of silly arguments like “you like him, don’t you”, and all that.
But, when I started to like this friend who we both knew, and he liked me too, there was complications. My boyfriend said that he didn’t want it open anymore, and this other guy told me that he didn’t want to “share me” with anyone else.
Sad actually, that they became so egoistical. I liked them both, but they forced me to choose. So I ended up losing both. So my advice is that you should really talk this through before deciding and try not to act childish.
I think it is a good idea in theory, but because there are people who may not agree with it, it will fail one day.
But if you don’t care about her that much, I think it’s ok.
i didnt mean to be mean or anything when i posted… just posted my own views on the subject… in the end it all comes to how you feel and what you would like to do… if it doesent bother you then sure, why not… but in my eyes when you have something like this i dont really see it lasting for long, but maybe one time she would ask for this kind of openes to end… then you would know she really love you…
I say just go for it. Have a good time, see if it works. Learn for yourself. Just keep in mind it’s beeen tried many times before, and most of them fail. Watch out for that 
I have to agree with Jack on this one. You can’t mix emotions with an “open relationship”. Things change down the line. They’ll change for one of you and then the problems will begin.