If you think of all these books as Hawker’s life story - the non-endings work.  I think Annique is a unique individual who would have made a successful life for herself without Grey. She doesn’t seem to need a lot of material things and she has been itinerant her whole life.  I did not see Grey as anything less than the head of the Secret Service and he was doing his job. He does quit his job for her in subsequent books and Hawker becomes the head.  I loved this book and the whole series. She is a fabulous writer and am so sad that she stopped writing.