Given the title and the first few chapters, it's very much how I expect it to go. Her ex will fall in love with her after she's gone and realize what he's lost and will try to win her back. But she doesn't love him anymore and will fall in love with her husband, the emperor.
If the writing is good, maybe I'll start to like the ex if he actually shows that he's going to become an ally and friend, moving forward in life as a better person after learning the lesson of losing his first love.