The Three Mrs. Wrights, Linda Keir
Ooooh, the antagonist you love to hate is Jonathan "Jack" "Trip" Mitchell Wright, III. He made my skin crawl and my blood boil - and I couldn't stop reading the train wreck.
Jack, married to Holly, has three children, an incredible company that if the idea of works, could detect childhood cancer before it manifests; all by a good-flavored chewable tablet.
John, meets, woes, and marries Jessica, a brilliant doctor, and moves her into his company to help him with the cancer-detecting tablet.
Trip meets Lark in a bar, finances her start-up, and becomes her fiance.
Of course, this will all blow up in Jack/John/Trip's face, but oh, is it fun watching it fall into place and then implode.
Seriously, someone please make a movie out of this one!