A Whole New Light by Sandra Brown
Cyn is discontent with her life and doesn't know why. She lost her husband two years ago and her mother moved in with her and her son when her father died. Her mother and her best friend Worth have been telling Cyn she needs to get on with her life. Worth was supposed to go to Mexico with a friend and now he has two tickets and needs a companion. He convinces Cyn to go with him and their relationship is changed forever. Cyn has to learn how to leave the past behind and embrace the future.
This is an old book of Sandra Brown's from when she wrote category romances. Good storyline of friends becoming lovers. It's a very easy read and typical of the genre. Vintage Brown with a good storyline and likeable characters.