You’re mistaking the sense of “being Gillovny.” My position is pretty easy to understand I think.
I believe they’re not a couple right now, I do believe Gillian is with PM and David’s with that chick, but I do believe these relationships have an expiration date because Gillian and David belong together and eventually will get back together. Also, I do believe that them still fucking once in a while isn’t out of the realm of possibility.
And most of all, I’m Gillovny because I WANT them together. Not because I think they are and always have been.