There was a book in the early 90's about 2 teenagers (step siblings) that fell in love. what was the name?

There was a book in the late 80's early 90's about 2 teenage step siblings that fall in love. There was also a seris of books that took place on the Western Michigan Coast during the summer. Also from the same time period. Any help with titles or authors name would be appercaited. ThanksThere was a book in the early 90's about 2 teenagers (step siblings) that fell in love. what was the name?
Maybe like the movie Clueless?There was a book in the early 90's about 2 teenagers (step siblings) that fell in love. what was the name?
Sweetheart, there are about a hundred books with the same plot. Can you give us any charecter names?





Are you thinking of Judy Blume? Sara Dessen?