My grandmother got married at 80 to a man she met at a social club. At my dad's 80th birthday recently, one of his rail enthusiast friends was happily flirting away with his sister, who's a few years older than him. (She's not interested in a relationship though she's had a couple of suitors since her husband died, through her dance club.) As long as you leave your home and socialise even minimally, you're going to come across other people your age.
I'm in my late 40s and have met a couple of perfectly nice men through online dating - one through an app, one on a website. I've dated some others who also seemed pleasant. I'm not out looking for a long-term live-in relationship, though, just a bit of fun, so I'm not limiting myself to men I think are "suitable" in some way, apart from being single.
But yes, there are apps and websites for people looking for all sorts of relationships; plenty of space on the internet for everyone. And plenty of things you can do offline - I've tried both, just had more luck online.
When I was in your situation I also thought I'd feel lonely, but in fact since my ex left I have felt less and less lonely. It turns out I just felt sad and unloveable as that was how it was at the end of my relationship. Before he left I imagined divorced life as me sitting in a dingy little flat somewhere with the dog, dreading the long evenings spent alone. Next June I really am moving into a flat (I stayed with the kids, now we are swapping), but my evenings are now busy, going to activities, getting exercise, meeting people, meeting up with new boyfriend who's revived my interest in sex :) - and I'm imagining a cosy little flat that I can make my own.
It's scary at that stage, but do you also feel a teeny bit excited at the prospect of a new start?