I'm Going to Rewrite the Devastating Novel - Episode 19

Okay so theory that may turn out to be a SPOILER (I just mean that I kind of hope it does because it would be interesting)

Don’t keep reading if you don’t want to be influenced.

It’s not actually a story, both her and him have returned from the future. She doesn’t remember what happened to her after she chose to leave last time (because she actually has his memories, but those memories ending before the following part )but I posit that based on the creepy looks, the tower Master gave her before that when she left, she somehow got kidnapped by him. Then once the ML (tentative) finally got his revenge he found out about whatever horrible fate that she got, horribly regretted her fate , somehow went back in time, and is obsessively trying to protect her this time.