Personally, I sincerely hope that HC doesn't do anything like this.
After all the time Luca has invested in Laura, taming her body, breaking down the walls in her mind, and the slow yet steady revelation of her true character, to throw all that away by having him pass her off to a group of randos? God, that would be so disappointing. Even as a bad ending.
Just my two cents, though.
I think the best bad ending would simply involve Harry moving on and being happy while Laura ends up either alone or in a loveless relationship with Luca as one of his women.
Then, one day a few years into the future, she'd be walking down the street when she would see none other than Harry coming in the opposite direction. He'd be smiling and laughing with a beautiful woman walking next to him and, walking between the two of them, a small girl who could only be their daughter. Laura would see this, see how happy he is with this new woman, with his new family, and realize for the first time just how much she has lost; how much she has thrown away. She'd stand there, paralyzed on the sidewalk, unable to do anything but stare at Harry as he gradually gets closer, dreading the moment when he would finally notice her presence.
But he never does.
He's so invested in his family that he just walks by as if she isn't even there. And, somehow, that makes her feel even worse. As Laura listens to the sound of their happy voices slowly fading into the distance, she remembers how Harry had once treated her with that same kind of single-minded love and devotion. As tears begin to fall from her eyes, she smiles to herself sadly.
...It was good to see that he hadn't changed.
Fade to black.
