I think I would go for both.
I would say "I want to get to know you better, I've always thought that it's easier to open up to someone who is also opening up to you, so I wanted to share a bit more about myself with you. (share not so pertinent data that might be interesting here) then...I'm an openminded person, prefer to surround myself with open-minded people, that's one of the reasons why my boyfriend and I have an open relationship, which allows us to each take closer friendships in a sexual direction that's acceptable for ourself and the friend. Not together (necessarily) that might have been confusing (giggle) just that we each accept that about one another." (his turn..)
"Love As Thou Wilt"