I honestly don’t believe PM and GA are a thing but how come her not being seen with a man means she wasn’t with peter but when we assume she’s spending time with David she’s also not seen with a man?

The thing is, not being with PM doesn’t necessarily means being with David or vice versa. The anon was assuming she was with PM because he was here but David was there too, so as she actually wasn’t seen with any of them, you can believe what you want to believe.
You all know where I stand on Gillovny, but I really don’t think that not believing in the PM rumor have to mean believing in Gillovny. I’m sure there are a lot of people out there who don’t believe in any of them.