I've been with this girl for about three weeks now. I think that both me and her want an open relationship as we like other people. Basically I want to say to her,

"Can we have an open relationship as I think we would both enjoy it more and it would make things more interesting".

Also I think I should convey it that I am in it for fun so I enjoy spending time talking to her just as much as I enjoy kissing her. I read that we should trust each other and tell one another what we are up to.

How Best do you think I should put this. Don't give me exact words, just tell me how should I convey it?