What's the Name of That Book??? discussion

The series has 3-5 books, and each book is quite long. I read it a couple years ago from the public library. The main character is a young woman who loves books and learning. I think this world may contain several planets, but it's definitely not got a sci-fi feel - no aliens, spaceships, technology, etc. Regardless, it's not set on Earth. I think the protagonist is part of a ruling family, but one that's not very important, and her family doesn't pay her much attention (except for maybe an aunt?). Toward the beginning of the first book, she is married (arranged marriage) to a young man who is a lord or something from another house/ruling family, and so she moves away to the city - and maybe country/planet? - he's from. Neither of them are very excited about the marriage, and the husband is very distant. Once in his own city, he goes off and leaves her alone - to live in his family's mansion, I guess? He's very mysterious, and he doesn't like his family. At first she doesn't want to trust him, but then she finds out about this spy work he's doing, and they decide to collaborate. He has a magic wardrobe in his room and she can use it as a portal or something to get to him and give him information. The husband is also very tall and skinny. Stuff happens - though it's not action-packed, and the writing is quite good - and somehow she ends up trapped in the working class (I think her inlaws hate her). The working class work in part for some sort of token - there are different colors: yellow, blue, etc. - that give you vacation experiences of a sort, I think. Toward the end of the first or second book, she works together with her husband to defeat these evil men who are trying to kill him and somehow are using mirrors as portals or something. Partway through the series, the mc falls in love with her husband, but toward the end he tries to disappear because he thinks it's best for her. It has a happy ending though, and they end up together. These books are all very clean. They also do not feel very modern, though I don't think they were written more than twenty-five years ago. The covers were solid colored with simple black and white sketches (I think one was a mountain; none had people on the cover). None of them contained horses, or really any sort of animals, so it wasn't high fantasy (also no kings, medieval-looking courts, knights, or wars). It also wasn't the mainstream modern kind of fantasy: the heroine didn't have any really cool powers; magic wasn't the focus; not constant action; not too focused on the romance either. Most of the series took place in the city, but I think outside of the city there were lot of cliffs/mountains, or maybe the city was situated on a mountain. The girl's original family didn't really come back into the story. There were no paranormal elements, witches, spirits, ghosts, elves, goblins, or aliens. AI's been totally stumped - I hope y'all can help me!

The Mirror Visitor series by Christelle Dabos? The first book is A Winter's Promise.

Thank you so much, Becca! I searched and searched but couldn't find it!