Ex-Fiance

Ex-Fiance is a character in "Rules of Engagement". He's got his first appearance in book 1, chapter 1.

Look
He has slick, black hair, brown eyes and tan skin,

Your Main Character
He had been going out with your Main Character for 5 years and had been engaged to her until she found him having an affair with Sabrina and breaks off the engagement. However, he joins the cruise and tries to get her back. His motivations increase when he finds out about her inheritance and tries to strike a deal with her to split the money 60-40 upon marrying her.

Sabrina
He has an affair with Sabrina.