You remind me of myself
When away, or when Z is away my mind has the tendancy to run rampant.
I agree with AutumnalTones that you are projecting your tendencies onto O, but I think even you realize that.
Being away from O has shown you how deeply you feel for him. Get that sorted first before giving in to other attractions. It does sounds as if you need to do some intensive communicating with O in order to do that. Just because you're apart doesn't usually mean you can't communicate. Sometimes it's even better because there's fewer distractions, if you know what I mean