Fantasy/romance about a hero coming out of a book to ask a female protagonist for help, and both go back into the book to save the world

[Judy]

This book starts in the real world with a female protagonist who (this part might not be completely accurate) reads about a male hero in a novel. Some time later, the hero comes out of the book because he needs her help, and she goes into the book with him, where they embark on an adventure to save the world. The hero and protagonist also become romantically involved. The antagonist is a demon or devil or something, I think? There might have been multiple.

I think I read this book around 2008. Any ideas?

[Abigail]

The Eyre Affair, by Jasper Fforde, has characters going in and out of books, and it's part of a series. The antagonist is named Acheron Hades. Not sure about any romance aspect (I haven't read it.)

[Ayshe]

Abigail wrote: "The Eyre Affair, by Jasper Fforde, has characters going in and out of books, and it's part of a series. The antagonist is named Acheron Hades. Not sure about any romance aspect (I have..."

The romance there was with person from her own world, not one from a novel.

[Judy]

I remember the setting being more of a modern-day if that helps at all.

[Kris]

Judy, can you tell us more about the heroine - her age, job/skills/interests, special powers, home location, etc.? Is this book for young adults (teens) or older adults?

Can you describe the fantasy world that they try to save?

Can you describe the book they go into - where she find it, what it looks like, what it's suppose to be about, etc.?

[Debbie is on Storygraph]

Between the Lines?

[Lobstergirl, au gratin]

Judy, are you still looking for this or did you find it?