Here's my two cents: Having this kink is a bit miserable when you're in a life situation where you know damn well that your chances of getting a fat girl to be with are practically 0% (mental health issues, never leaving the house, living with family by necessity who are VERY vocal about hating how fat women are getting nowadays, not having anything good to offer a prospective partner in a relationship in terms of being an interesting/fun person, etc.), and you have no real prospects of leaving said situation anytime soon. Granted, internet access and porn help alleviate that emptiness quite a bit, but you can only trick your brain so much for so long before it goes "right, homie, we both know these images you're looking at and the hands you're stroking your dick with aren't actually an obese woman, who the hell are we kidding here?", and the sadness creeps back in again like morning fog from the ocean rolling inland.
It feels like I'll never get to actually be with any woman, much less a big one, and that's not exactly doing wonders for my mood. I'm already on some pretty heavy antidepressants as well for brain chemical shit, apparently this crap cuts like a knife through even those, despite not hurting my dick function at all.