Also, it wasn't just Kip. Every PoV character was focused on sex an absurd amount of the time. Every single one. For one character it might actually make sense; it's a major theme in their stream of consciousness that the reader should be aware of. For every character? It's a major theme in the author's stream of consciousness that he couldn't manage to keep hidden for longer than 2 pages.
Another thing you mentioned about every POV, it is really only Kip's POV where it happens. You get a lot of Gavin and there is really no sex outside of the minor part with Marysia visting him. You have a lot of Teia and almost nothing as far as sex goes with her. Same with Karris.
And I will add that while you can still find it annoying to read (I did at times myself as well), keep in mind we are talking about a teenage virgin here with a hot ass wife. When I was that age more or less 90% of my day was taken up with thoughts of sex. Even at my age now it is probably close to 60 or 70% lol. So the author is giving what I would say is a pretty spot on portrayal of that type of character.