Nick Rawlings is a commercial airline pilot who has a stable home life in Dallas with wife of 16 years, JoBeth, and their son. He has also been married for three years to Allison, a Chicago business executive, and is about to tie the knot with a young blonde named Miriam who lives with her father in Hawaii.
On the approach of their anniversary, JoBeth discovers a receipt for purchases of over $9000 in Nick's convertible and is all excited, until she finds out her gift was only $350 of that amount - and the rest of it was an engagement ring. After this discovery, she and a private investigator find out about Nick's marriage with Allison. Thus she begins the end of their marriage with a slow but methodical cut off of Nick's access to their money and all that he has worked for.
Meanwhile, at the same time, Allison is planning to relocate to Dallas with her company and has ironically bought a house just a couple of doors down on the same street as Nick and JoBeth's house. Also, Miriam accompanies Nick back to Dallas to spend more time with him, and slowly learns the truth herself.
With Nick's life crumbling down around him, and all three women closing in on each other, the lesson is learned that two is not company... and three is definitely a crowd.