Bye Bye, My Boyfriend!

(from ebookjapan):

The trouble with Bonnie, a jaded girl, is her beautiful and irresistible older sister, Marilyn. She's a wicked woman who can't even break up with her star-studded BF, even though she has a fiancé, Tony. "The only man my heart is set on is Tony!" Shocked by Marilyn and her nastiness, Bonnie's problems will be solved if her sister gets married. So Bonnie decides to help Marilyn sort things out with her BF (boyfriend...)

Included are the one-shots "Wester's Girlfriend" and "Cathy's First Love."