Much of Adrien's behavior makes significantly more sense in light of how both his parents treat him:
His Lack of Empathy for others is a shared family trait — Gabriel and Emilie have no concern or care for anyone beyond themselves, including their own son. Nor do they care about how their actions affect others beyond how they personally benefit from it. Adrien did nothing about Lila, even though she was scamming his classmates and hurting Marinette simply because she wasn’t affecting him, and because he didn’t want to deal with her potentially getting akumatized, creating more work for him as Chat Noir.
Adrien specifically believes that as his girlfriend, Marinette is obligated to bend over backwards to accommodate him, putting his every wish ahead of her own. This is exactly how his parents have tried to raise him to cater to their every whim — he sincerely believes that's what love is.
Which makes it all the more triumphant when he washes his hands of his parents and moves forward with his aunt and cousin (and starts to think of the latter two as a mom and brother respectively); Adrien has realized his parents' (and his) behaviour isn’t actually love, and that he needed to change, shedding off their influence and beliefs.
Also to note, while Adrien does lament that he wasn’t ‘good enough’ for Marinette, he does ultimately let her go in the end. No doubt Emilie’s speech (particularly the part about how naive he is to think that she could be convinced to hand over her earrings to him) had finally opened his eyes to how wrong he was to expect Marinette to cater to him just because ‘she was his soulmate’ and that he really hadn’t thought or cared about what she wanted at all.
Also to note, he has shown that he can be manipulative like his parents. Prime example of this is when he pretended that he had Easily Forgiven his mother, allowing him to snatch the ring back.
