What is the title of a book I'm searching, given the following description?

It was made in the 2010s. My clues for what the book is are not very much, so, take what you can.

Anyway, the main protagonist was a man, which did sorta important job. Maybe a lawyer, a policeman, a psychologist, or anything like that. Anyway, I think he had a mansion/villa, and didn’t love her wife (not so sure about “wife”, but…). He left the villa for sex, I think.

Anyway, when he returned, three things may have happened: a) he left her. b) maybe she disappeared from the villa. c) she was murdered. These are the three main things that may have happened.

Anyhow, after this, he traveled to another city by the sea, to meet his ex wife. I know it’s by the sea, because one meeting between them takes place on the dock. She had a grudge against him for something he did in the past. She says she must have some time for herself before him and her becoming a couple again.

Then there’s 2 main hypothesis of what may happen: a) he gets some menacing letters (maybe by the car’s wipers). b) he notices someone following him, maybe a stalker.

Anyway, I skipped this part. What I can say is that most of the book revolves around people asking him and other witness/suspects questions. That‘s the big catch.

a) If this is a legal thriller, they might be lawyers, if it’s a domestic thriller, it might be the police. I’m leaning more toward the domestic.

More information: b) There’s also the question that this book might be a stand-alone or part of a series. I lean more toward the standalone.

c) Is the book in first-person narrative or third person? I lean more toward third-person.

That’s all. Thank you all for helping me find this book.