Girls, How do I bring this up with the guy I’m seeing?

So I have known this guy for awhile now and we have just started seeing each other recently and it has been AMAZING last few weeks we have this thing we call each bubby etc, the other day he mention to me that I’m basically his partner but we haven’t made it official I don’t want to do the wrong by him talking to anyone else (guys) or go on dating sites if we are dating

I also want to bring this up with him but don’t want to hurt his feelings and make it official if that’s what we both want etc.. even though it’s still early days

Girls, How do I bring this up with the guy I’m seeing?
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