Wishbone: Are there any adult games with sexual content that aren't Japanese or pretending to be Japanese?
Depends. Do you class "coded with RPG maker 2003 with 8 bit RPG look" as "pretending to be japanese"?
You might, since the whole graphic style is a wink to the (very) old JRPGs, although pixel-art is not purely a japanese artstyle.
But if you don't, you might try "Embric of Wulfhammer's Castle".
Although for this one, I would suggest to play without the "mature art" (it can be disabled when you start the game), as I found the story and 8-bit pixel art actually more suggestive than the very amateurish "mature content". So that might defeat your "games with sexual content" specification. ^^