I like reading about taboo feelings. I read ones with priest (Craving's Creek by Mel Bossa; Vespertine by Leta Blake & Indra Vaughn) or with biological father and son (Quillon's Covert by Joseph Lance Tonlet & Louis Stevens). Do you know any other books with forbidden love? Which are your favourite? Maybe some with stepbrother? Or any other taboo. 
Hi
Max .Vos - Going Home
https://www.goodreads.com/book/show/23383765-going-home
Father/Son.
Really good book.
Mamcerri