Pretend We're Over by Ella Miles

Ella always pulls you in and makes you think you know what's going to happen, but then you find out you don't know a thing. Sebastian and Millie both have difficult pasts, but their futures seem to be heading in the direction too. Being fake married to each other proves to be a challenge for both of them, but they both find they think they don't need someone to make their lives better but they both are wrong.