I do feel bad for ML when she decided to leave him to go back to her own world/reality because he was still unsure about his feelings for her and the oriFL.

And I think his feelings are valid and realistic, considering he was in love with oriFL for years, and was only beginning to love MC through their arranged relationship/engagement (which happened in the span of months).

Also as a good person, it will be weird for him to turn oriFL away when she'd turn up on their doorstep drenched from the rain. He even said he would have to ask for MC's permission if oriFL wanted to stay at their place. So even though it was disappointing that his first reaction was to 'rush to' oriFL instead of MC, he still remembered about MC immediately after. Like I would be concern too if an acquaintance of mine came to me like a drowned rat crying their eyes out.
Just wished she didnt have to die a violent death/car accident, because he then lived with regret his entire life believing he indirectly caused her death that night. Wished the system had swapped her soul for like an AI who decided to dump him and moved abroad or something lol