Yeah, lore is there for anyone who enjoy this as a real game not just an erotic one. I'm sure you will love what's coming in future. Note that it will change as the game development progressed as I will be comfortable to share more things.
There are two hints about this. Masuo conversation with Momoko where he tells her having sex with Hitomi feels like her. Momoko has a tennis app. There are also minor hints like her name being Hitomi in asylum levels. She changed it after her husband left her.
As for the part that she lust for him, you will understand it after a future and when you will notice certain changes to a place that can be accessed with portal.
But real Hitomi Ito character actually exists and it's her niece. Her sister named her daughter Hitomi because her love for her sister.
If you are enjoying this now, just wait until Ryoko dies.