A 1970's middle age couple with 4 children write a sex book with artist drawings of them in the various positions. The children find book and go through it together, ranging in age from around 14 or 15 to like 5. Book doesn't really cut to the chase on much right away. It bounces to what some of the kids are doing now like 20+ years later. More shocking or surprising stuff comes later, spoiler I guess but since book from 2005, I guess long enough so too bad, the marriage ended soon after book published. The artist fell in love with the mom and she with him and the 20 years later they are still together. Dad is still stunned or bitter about it. All the kids have a kind of screwed up life, from the book or from broken marriage who knows, you get to figure that out. Of course the 3rd youngest is probably most normal & secure with himself and he is fighting cancer but his partner is there supporting him. The book points out in more than handful of places his bazaar life is that he is a gay Republican. Okay story and characters, I just couldn't really get into it very much. Had a hard time caring about any of them. Oh well.
There is 1 WL for it so I will probably post it at some point & ship if off if the WL is real.