I see. I think It's a bit of a shallow way to do it. It'll feel more like a game with erotic content pinned to it instead of an erotic game by itself. That said, I understand that most erotic/porn games do it this way and you might even choose to do it as a design decision. After all, It's hard to incorporate and blend erotic content meaningfully into the gameplay.
I think AA2 does it well. It's a sandbox game but the challenge comes in figuring out different character archetypes and getting them to like the player character and even once you do get to the sex scene, there's still mechanics like sexual compatibility as well as unlocking new positions. The game also doesn't end then and the character you romanced acts differently after and keeps acting differently the more sexual interactions you have. They may even influence other characters in different ways (deter them from socializing with you if they're jealous or try to get them into a threesome with you if they like them, etc.)My point is the nsfw content is meaningfully incorporated into the game flow whereas your current proposition (at least how I understood it) seems somewhat meaningless. A typical "win state/fail state" reward mechanic.
Perhaps you want the erotic content to take a backseat to your game which is up to you at the end of the day but it does feel like a half decision to me and I personally won't appreciate it as much. That said, it's something to think about. Hope you make a game as great as you want it to be!