Pure distribution:
Here. That feeds a bunch of other game sites, but most of them don't have a real community
itch.io. Nice people, easy to set up, has payment solutions
Gamejolt.com. Slightly more complex to set up, looks nice, haven't had any real traction
Steam. Pain in the ass to set up (big know your customer process, $99 submission fee, Steam Workshop is... fun). But huge audience, and amazing dev tools (most of my testers use Steam for beta builds now)
I don't know of anyone doing porn on GoG/Epic
There's a few Japanese sites, DLSites, etc. Sales of non-japanese language games aren't great, and you need to censor.
If you have a Web playable, Newground is still huge, and it's an audience that doesn't overlap much with the others
If you're following some specific fetishes (furry/hypnosis/transformation), there's sites that give really good bang for the buck (such as it is).