I really hate those as well. But overall I'm not into sex scenes in books from which I expect something else from. For example in King's (horror) books there's always this semi-random sex(ual) scene. I think maybe the authors just personally enjoy writing them? Or think it makes it more immersive? Or there is indeed a part of the audience that really enjoys them? Hard to tell for me

All my life I absolutely loved romance books, but every time I'm in a romantic relationship I prefer anything else, and my genre horizons are broadened as well. I explain it by more easily noticing a lack of a truly genuine connection between characters in romance, and being more eager to try out books (movies, games...) my partner likes. Though I think changes in your (inner) life may really affect your taste in different ways as well.