I kinda agree on your take that the sex scenes are getting redundant. However in my opinion, Lester and Sarah’s scenes makes this series interesting and enjoyable. The slow development of Sarah’s feelings towards Lester is pivotal. Small changes like saying she loves him is what me as a reader look for. I think DS should mix it up on the location though. So far their sex scenes were always the apartment, office, home, parking lot and hotel. Now that Lester is her direct superior he can disguise a trip to Paris as a work conference but in reality he’s taking her to their honeymoon and leave Dan behind helpless. So Lester can openly display themselves in public as a couple. DS can then add new sex scenes like on a yacht, a public restroom or on a plane. So many new possibilities to avoid the redundancy.