That’s what he thinks. Till now the story has been about what others perceive to be Ai’s wishes and thoughts. Remember the director telling how Ai changed around 12 yrs and started to look mature and in love, that means she loved him in her own way. And it looks like she slept with him out of consideration and to comfort him. She dumped him probably because she got pregnant and didn’t wanna burden him, like he younger and that would ruin both of them.
And u should know all this is his own delusions. Clinging to her was his choice not forced on him. She had no responsibility over him, she doesn’t own his life just like how he doesn’t own hers. It’s femicide!
This is, if I dare say, your explanation: "ai fits codependent as well since she puts the needs of others".
Hardly understandable, but whatever. You know how many people fits the bill? Mostly all parents in the world with their children. Not saying your definition is exclusive to parenthood, but so generalized that anyone can relate to it.
Ai is far from codependent. I don't know how you checked your boxes to arrive to this condition, but she sure does not need Hikari to find fulfillment in her life, feel the need to compromise her values to be with him, nor to put his needs above hers - she never did as far as we know. She is a free-spirited person, and I put an emphasize on the "free" part.
Codependency involves individuals being "mutually" dependent of each others, especially a relationship "addiction". Like the user above said "Ai wasn’t really dependent on him. Otherwise she wouldn’t have dumped him". Not seemingly addicted, not trying to worsen Hikari's sake (blatantly honest with him) for her gain, not even working hard on her manipulation skills... She was "vibing" and "going with the flow" at this point.
It is far from right-sounding to say that the free-minded and quite narcissistic Ai would feel like "depending" on Hikari (which what codependent implies). Finding someone pitiful and seeking love from any opportunities do not systemically mean you are emotionally enslaved to that one person.
You'll have an easier time convincing yourself that Ai shows Narcissistic traits than her being Hikari's codependent.
there you have it; codependency kills! literally!