That's because the love and lust that every girl feels for Akira is fake, and it's meant to be that way because those feelings were implanted by the Gods, the Gods want them to love him, they were "meant to be"
An example of this is Sana, and how angrily whoever it is that controlled her to like you gets, when you refuse to plap her.
Ami's love seems unnatural, she keeps hearing voices and they might be the ones steering her into fake love. Touka's love seems unnatural, she thinks Akira is disgusting at the beginning and somehow by being even more perverted she develops sexual feelings for him, it doesn't make sense to me. Maya's love seems unnatural (to me at least) as well, no matter how much you say to me that well "she has been trying to find the real akira for thousands of years" fake love can last for this long too, many girls' love feels unnatural the way they dont think much of him and then all of a sudden want to fuck w him out of the blue. Wizard Noriko and Maya just developing feelings at such a young age and wanting to plap Akira from that young is also unnatural, this simply does not happen and I just feel like they are all manipulated. They are "meant to be" manipulated.
Ayane for me is the only person whose love feels natural (despite it being obviously wrong) but whos to say that you can't love someone even if it's wrong? From the start of the game, she's the one character that has been declaring her unconditional love for him, she's the first character you commit a sexual act with inside the game (Akira was already plapping Wizard Maya way before the game's start, but for US she is the first one) She's the only one who would put up with ANYTHING Akira does, from having him cheating on her, to having to endure Kirin, to having to share him with Chika all to please him.
And while you can claim that Maya or Ami or many other girls know about his polygamy and don't want to share him, not a single one of them reacts the same way Ayane has. They are all either annoyed, angry or even accepting, which is not a genuine reaction to having your feelings hurt, not a single one of them acts truly heartbroken as Ayane has. All they want is to be loved by him by any means and that's not because they are putting aside their feelings, it is because it's their utmost influenced GOAL. They will get angry and will seek him out again anyway.
She's also the only girl in the game that has told you exactly when she fell in love with you, no other girl has done it, or can do it, because they don't possess such memory. The game has been practically screaming at you since the very beginning that AYANE LOVES YOU.
She was not "meant to be" because her feelings were never "meant to be" real, which ironically makes her the one Meant to be.