honestly this book was sooo good and you should 100% read it it’s so well written. i would say that yes he does cheat on his partner with the fml but i didn’t really find it that frustrating bc he makes it clear that he likes the fml more and eventually breaks it off with his ex. also he’s not cheating for thaaat long only for a short time period in the middle of the book. also since you wanted to know, the ending isn’t reeeeally a happy one bc spoiler well jk is in prison. but there’s a second book right so you never know???? but i feel like the ending isn’t even that depressing.
Anyway this book was sooo funny and emotional and really good i think you should deffo read it.