
It's in her memories. As I said, it was before mc took over Violet's body. The original Violet used the guy to test the Duke's love for her, non-drunk, completely sober leading to their break up. Maybe you should go back to re-read. The novel gets into it more but the original Violet definitely played the Duke and only regretted after losing him

he, while claiming to love Violet before the "cheating " incident still stayed close with Sharron despite literaly everyone and i mean EVERYONE being able to see Sharron liked him and disliked Violet.. you can pretend all you want that he did it out of Nobel etiquet and all that crap... but even before said incident he just stood by and watched as Sharron made snody remarks about the woman he "loved" under the pretence of a chat.
And after the incident she literaly begged on her knees for forgiveness from him.. and his thought process was.. il stay engaged to you despite being unable to forgive and il flirt with the person that will hurt you the most and alow said person to redicule you. But the second she gives up .. he is back on his knees begging er saying he love her and will forgive her cheating..
So its ok to torture your fiance who "cheated" even if they never ment to but was set up by someone who is jelous of her, whom you them openly flirt with while still engaged?
If he was so blody hurt he could have ended their egnagement.. but he didnt, he loved seeing her in pain while also loving Sharrons atention.
Ch. 15,
Honestly, Im kinda feeling bad for the duke at this point since it was the original Violet who cheated on him first. And maybe because I really like his looks (hidden motive spotted) ╮( ̄▽ ̄)╭