@WhisCalifa69
Oh, it's interesting that you read one of the main themes as "lack of communication". It is a important theme, after all that's the thing with the main couple... Haru and Souta want to be together despite of the money, but they actually think that it is money that joins them together. If they could be more honest the situation wouldn't have escalated as much as it did in such a short time.
But that is not the premise... At least not how I read it. It's more of a "Most forms of abuse often come from those that claim to be close rather than from acquaintances" and the derivative thought that I define as the purpose of the psychological terror genre:
This could be happening to the kid next door.
There's also the underlying themes of "Innocence = Pure" "Ignorance is bliss" but "Ignorance leads to irresponsible behaviour" and most importantly "Love isn't control"
And I just realized that the author is doing a good job at getting across the complexity of the situation... Well, that's why we come to suffer with every release I guess.