Lady jumped in front of an arrow with a big book, which had been poisoned

Read this book 2010/2011. Book had been amazing but for the life of me i cant recall the name of it, or the author. PLEASE HELP
Historical Romance, at the start of the book they had all been in a church for someone's marriage, and the lady/heroine had saved a man by jumping in front of a Poisoned arrow which had been meant for him. She had caught the arrow with a big heavy book but it still had penetrated the book and pierced her skin. The man then offered to treat her and in the process she made him take her back to his home (he was a widower with children and also an inventor....why he had almost been killed). She stayed with them, helped solve the mystery of who was trying to kill him and the the end they fell in love.