I've been van lifing for 4 years, and I've never wanted to return to houselife. Pooping in a bag, as I do on occasion, is a small price to pay for nearly limitless freedom.
Anyway, to answer your question - mostly I dig holes in the wilderness (there's nothing like a poo with a view, seriously) or use public restrooms, but when those aren't an option (rarely) I poop in a bag meant for dog poop (I have great aim) so when I dispose of it, people are just like, look at that conscientious citizen cleaning up after her dog. For times when no trash cans are readily available, I put that bag in a litter genie. I've had weeks worth of poop in that thing and you can't smell a damn thing from outside (I had this verified by strangers in case I was nose blind)
All pooping aside, vanlife vs. houselife is all about which sacrifices you're willing to make. You've stated yours here. To each their own. But if I were living your life, I would literally be climbing the fucking walls.
The way I see it, the human population has always had nomads and settlers. Doesn't it make sense that for some people, those nomad genes would persist? I'm so much happier in motion.
That said, I live in a "house" with little temperature regulation, limited space, and questionable cleanliness. It's not for everyone. But paying rent, which necessitates working more hours, which necessitates spending my life doing things that other people want me to do for money - that shit is not for me. I can put up with a lot of physical discomfort to have my freedom.
But I don't get what you're saying about natural disasters. I can drive the fuck away. You're the one who's stuck and will lose all your worldly possessions if a natural disaster comes your way,
As for the man-bun boyfriend - I could never put up with THAT. My van is my own, damnit.