I think it was real, and somehow still is. Gillovny is always real, no matter what. I think they were a couple from circa 2011/2012 ‘till the beginning of the summer of 2016 at least. I’m not quite sure Gillian and PM were really “dating” when the rumor started in October 2016, or it might have been the very beginning. Sadly, we will never know what happened between Gillian and David. I’m just glad they look okay with each other, which should make a great season 11 Gillovny-wise, at least, if not for the plot. So that’s something. And hopefully, they’ll get back together soon.