I can't remember the title of the book

I'm looking for a certain book, but I can only remember scraps. Genre was horror / thriller (romance), please help!

Hello dear members!

I hope so much that I can be helped. I'm looking for a certain book that I once got on loan from a former boss. Unfortunately, I don't have a good memory, so I don't remember the author's name, just like much of the plot is blurry. The points I know are as follows:

- The author is very inspired by Stephen King

- He definitely wrote a book that had angel wings on the cover (but doesn't have to be the book I'm looking for)

- The book I'm looking for is about a protagonist who keeps traveling back in time (I think he comes from the past, but I can be wrong)

- The female protagonist gets to know the man a little through his travels, how exactly is unfortunately unclear to me at the moment

- I definitely know that in the end there was a situation in which one of the two tried to travel back to a certain point in time to save the other. That didn't work, so they tried again and then realized it didn't work as you couldn't travel back twice at the same time, so they sent an item (I can't remember which one anymore) to that point to be given to the other character rescue

I know these are little clues and I apologize for that! As mentioned, I generally don't have a good memory, but I really liked the story and would like to get the book myself. If anyone knows this book, please tell me!