
To make you feel better! OG fiance liked the ML sister! And she got killed. They got closer because they were grieving her.
Now MC and ML tries to saver her.
The summary of the second volume in yes press :
" Ever since Ibuki spilled the beans to Baba about his time leap, their relationship has grown closer than ever! The two even teamed up to stop Baba’s sister’s murder. But when the day of the incident passes and nothing happens, Ibuki realizes the future has changed. Does this mean Baba’s sister is safe? As Baba grows distrustful, will Ibuki be able to protect this new life...? "
It's established that the sister was loved very much so i don't think OG ML and OG Fiance, if given the choice, would be against saving her even at the cost of their relationship ...
I hope that the marriage news was just a misunderstanding. I'm not comfortable with the fact that mc traveled to the past just to steal him away from his future fiance