I'm having so much fun with this already. I suspect how this is going to go, but I'm secretly hoping for a twist that the force of the story is what made the ML fall for the FML, because I just find it sus that he broke off the engagement and then SUDDENLY wanted to reverse that when the story started.
...But it's also possible he did it to save her from his dad only to be like no I love her too much. Which I won't like nearly as much since it'll make him an idiot.
There will come a part in the story where it warns you not to continue if you want to keep the happy ending. DON'T CONTINUE. It haunts me to this day.