So do you really believe anything at all has ever happened to them behind the scenes? And if so.. why would Katherine sign up for a foreseeable future filled with this? Nothing about this relationship makes any damn sense.. fast food binges and 2 hour slots of late night videogame music over gin (kill me now) are supposed to make up for a danger-filled antisocial pet confinement horror show with a man so inept he can't even do the bare minimum to send a package back to amazon within a reasonable timeframe? Why not order another instantly for next day delivery with your prime sub because you know they'll make sure you get your refund in a week's time.
Most DSP - Kat relationship speculation works on the assumption that theirs has been, should have been and has at any point been remotely normal. Someone please correct me if I got this wrong but I believe Phil saw her over the course of 4-6 secret weekends before they moved in together. Kat was having relationship / financial problems and Phil was desperate for another mommy / trophy. On the halloween stream six months? later we were witness to the complete lack of chemistry and affection between the two, despite Phil's attempts to show off how much of a loving couple they were. Then on top of that she spends her free time in her own room, playing games on a tiny screen when there's a comfortable, likely overpriced couch and decent size tv (plus the fireplace she loves!) downstairs. Nothing but red flags, man.
There's this expectation from Kat and other relatively normal women who shack up with lolcows that they should jet and seek out another man. I don't think anyone can disagree that Kat can do infinitely better in terms of finding someone who is not a weird manbaby like Phil. A man who has basic life skills, whose physique matches his age, has friends, takes care of his parents and whose aspirations go beyond "Keeping my begging empire".
My hypothesis are that she's not interested in a relationship with an actual man and that there's two likely possibilities, though both revolve around Kat "taking advantage" of Phil.
"Kat be crazy"
We know Katherine has mental health issues and from her documented interactions with her ex and Phil she is clearly "off" socially. She knows how to kind of behave as expected but I think it takes a toll on her to pretend to be normal and comfortable. With Phil she doesn't have to. Phil is both weird himself and willing to accept pretty much anything in terms of relationships as long as he can pretend to be a big man on the internet. The fact she games and sleeps in her own room isn't an issue. In Phil's reality only the literal, factual truth of her being a woman, living in his house and being married to him matter, even if it is all in the context of a loveless, mutually beneficial partnership.
Kat just found a comfortable place to rest her tired, broken brain from the expectations of normal relationships. Perhaps she'll mend her psyche and move on. Perhaps not. It could be Phil who breaks down as his prospects diminish and the shine on his serious-adult-life trophy tarnishes. Kat better not get sick any time in the next 40 years, physically or mentally, Phil ain't got time for that.
"She a gold digger"
I find this one less likely because while Phil makes a lot of money, evidence would suggest he's terrible at managing it and thus has no money for her to take. Pignosis aside, Phil's miserable six days out of seven and hasn't taken a staycation in forever. Unless this cant-be-bothered-to-shave and stream-in-my-pajama person found the mental reserves to knuckle down and deprive himself of essential phil-style-luxuries he's just about staying in the black and Kat has nothing to take now or when she divorces him.
I could go into how Kat supposedly has a job and that no gold digger would stand for that, but this second hypothesis is heavily dependent on Phil's words, whereas the former is sourced in facts and documented evidence so the gold-digger hypothesis doesn't carry much weight.
Bottom line for both is that Kat has other priorities than being with a "real man" right now and that's why she's not bailing on this freak show circus act.