Well we don't know if he is a good guy. Remember he has beef with the Emperor cause of how The Emperor's father treated his mother as a concubine. He had wanted veagence on the Emperor and his line. He did feel bad for using Rashta because... let's face it. She would've been happy just being a concubine... but did he help break them up cause he wanted Heinly happy or for vengeance? Or both? Why did he take Rashtas kids? Did he feel guilty? He is so mysterious.
Oh the marriage... oof... so they get married and guess who comes to the wedding? Yup... and Rashta was like "glad you're getting married despite be barren" remark and everyone was pissed... especially the Emperor. Also he tried to convince Navier to not get married and she called him out on hypocrisy. ... and that was after the Empress had to hide and was on the run

Duke: I hope you get home safe
Queens gaze: I hope you die