Packing for your next trip is like preparing for a diplomatic summit. Your luggage is your aid package. It’s a good idea to exchange some money for local currency and to break it into small bills so you’re not stuck searching for change when you need it. A list of key phrases in the local language of a foreign country you’re visiting can come in handy, as well as a mini first-aid kit stocked with antacids, pain relievers, and motion sickness medication. That person is a peacekeeper, calm in the face of trouble, pulling out a bottle to remedy a headache. Gum or mints are another good item to pack. Fresh breath is key when you’re stuck in close quarters with someone all day.
This novel looks and reads like the novelization of a mood board. You can practically see the images that the author used to help plan the book on Pinterest – rainy night shots of city skyline viewed through smeared windows, particularly grimy hotel rooms with unmade beds, two wine glasses left on a room service cart in a damp wipe of a towel. The aesthetic is paramount and works beautifully to create a consistent, rich and melancholy atmosphere of high-end loneliness. In many cases the plot and characters seem to have been designed to support this mood rather than forming the basis of the story in themselves. A book to read when you’re alone and it’s raining outside and you want to feel sad in a certain, very cinematic way. If you’re someone who chooses books by ‘aesthetic’ then this is a great choice.
My answer will probably differ from what you expect given how you worded your question. I'm familiar with the "mature woman" or "cougar" genre of manga that typically plays out within the home of the older woman. As for "mature beauty" there are certainly manga labeled under this category but that's a rather different kettle of fish. The "curvy step mom" situation that you apparently are looking for would likely be categorized under a particular tag found in adult oriented Doujinshi. I'd caution that while there are stories with older confident women and young boys, you're unlikely to find these in mainstream shonen or shojo manga (the two genres of manga most popular with children and pre-teens). There are many Office romance stories and stories about the relationship between a landlord and his tenant in Josei or Seinen manga. They're commonly translated and read by adults, and usually have older confident women as main characters. While there are stories with step families as main characters, these are extremely unpopular and generally considered to be a topic that is far too complicated and negative to be written about in manga. Such a story would probably try to avoid making the relationship between the main characters too obvious and would likely imply a relationship outside of the typical family dynamic.
You'd likely find a lot of unofficial, fan-translated adult content when searching for the phrase “curvy step mom” on mainstream manga sites. This is a completely different arena from what’s discussed in general forums regarding mainstream manga and so should be approached with caution.