Something like fate / Colasanti, Susane

When Lani meets Erin's boyfriend, Jason, she feels an immediate connection with him but she ignores her feelings rather than hurt her best friend. But when Erin goes away for the summer, it becomes harder and harder to ignore him or her feelings.

Lani and Jason, who is her best friend's boyfriend, fall in love, causing Lani tremendous anguish and guilt.