This is really a shame. While Frustration isn't the best adult game I've played, it is a very good one, and I'm sorry that you're stopping. I appreciate that you're being upfront about it and I support your decision; you should do what you think is best for you, whatever that is.
But I also hope you'll reconsider. I don't know that much about the economics of the adult game industry, but if you're within 12 months of completing the game... Well, a Steam release could be really rewarding, I think, even with all the hoops they make you jump through.
In any case, I wish you the best and I've really enjoyed your work. I hope you find greater success and satisfaction with your next project.