For those not in the know, this is a romance manga with ecchi elements, not an H-manga. The sex scenes are for plot development and for artistic expression (especially for the inspiration of the characters in the manga itself who are mostly artists) and not there to be particularly sexy. You can see this in how vanilla they are, and increasingly feature the main monogamous couple more and more.
You can read the translated chapters on Mangadex (up to a certain point) I can vouch for the quality of the story, but the manga gets less and less sexy over time, and more and more about the romance plot and the advancement of artistic skill. Personally, I like the story, but the eroticism of the manga drops every volume, with 3 being the last one that has anything interesting, imo. It peaks early and keeps dropping. This is a romance / art drama with some sex in it, not a porn story.
Good for what it is, but it's not an H-manga, for those who are looking for one.