True felix where very pitiful but this is for his own good he is too naive he doesnt know how to deal with annoying womens and it will be just more difficult in future for them so why not
Adele is very smart and being a typical girl that she is
How would Adele know what's good for Felix and what's not? The duke has his own mind, opinions, beliefs, and so on. He can think and make a decision for himself; even if he's naive like you said he's a full grown adult. Besides, there's no guarantee that if what Adele has planned worked means that they're never getting any marriage problems after. In real life, a healthy married couple still gets problems/small fights. It's part of being married.
Guiding someone is one thing but manipulating them into doing your bidding is another. What Adele has been doing is the latter.
"Perfectly reasonable", he told her he's unsure twice... he's obviously in love with her to the point that it's readily apparent to as anyone who's served the duke, she let his density slide for a bit and after being told "I dunno" TWICE she decided to do a pull tactic because it would kill two birds with one stone. It kills the rumors and she gets to be chased by him a bit since he was being wishy-washy.
Like I said before I understand Adele's actions but at the same time the duke's hesitation in answering Adele's confession was perfectly reasonable.
He had a trauma that made him unable to trust women, and it was also the first time he ever fell in love. Adele is forgetting their whole relationship was based on the contract that they made in the first place, that SHE AGREED WITH, so I don't understand why she's complaining now about Felix just "using her" to solve the problem with Susan. It was part of the contract.
And to top it all off, Adele is kind of pushing the duke into doing what SHE wants - is it so difficult to give the man a few days to breathe and really think about his and Adele's relationship?? Give him some time to think??? He was so busy with dealing with his own problem with Susan and basically the whole kingdom (since the problem involves even the crown prince) and Adele here is only thinking about herself. When she and Felix finally met after the problem being solved she showed no reflection of empathizing him. Until the end when she's talking about their relationship her concerns centered mainly on her, as if Felix didn't get affected by the rumors too.
If she was really planning on giving him some space by leaving Felix's mansion, then why does she have to manipulate the whole thing in her favor, making sure he does EXACTLY as SHE wants? I know Adele has been through a lot with what happened and all but yes, in my opinion this is definitely unfair for Duke Felix. He's being lead left and right like a dog on a leash. I don't even care about the ending anymore I'll just assume they lived happily ever after. ┑(￣Д ￣)┍