Saul and Patsy by Charles Baxter

I explained how Saul and Patsy by Charles Baxter came my way by default as a recommend alongside Elizabeth Strout's Abide With Me and finally I've read it.
East Coast graduates, Saul and Patsy move to Michigan and settle down there to life as newly-weds, it's not what they had planned but Saul feels driven to live there.He teaches in a local school and first baby arrives on scene.
The book got off to racing start with me, not so much for action packed content but for the unusual and I thought amazing way in which Charles Baxter delineates the role of a new father.Saul is confused and uncertain about his new role and Baxter handles this with ease
"To him fatherhood was one long unrevisable bourgeois script full of unexpected plot turns and predictable blow-ups in the third act, but that was the script he had been handed and now he was in the play." It's a lesser known fact and frequently one that is scoffed at, but the research shows that men suffer from post-natal depression too and I thought Baxter nailed that here, possibly unintentionally? It's the first time I've come across it in a novel.
Life settles into what I imagine to be American small town routine but then things take a bit of a turn for the unusual verging on the horrific at the hands of one of Saul's remedial students Gordy Himmelman and life changes forever for Saul and Patsy. It's a sort of Lionel Shriver-Kevin scenario with difference.
The second half of the book is taken up with sorting out the mess.
On reflection there are no other endings Charles Baxter could really have opted for but somehow the book lost its momentum  for me in the final chapters and I ended up feeling mildly disappointed, nothing I can put my finger except to say "so what was that all about then?"
Plenty in here that I did enjoy and I was happy to complete but I think I've missed something and I'm relying on Scott Pack to explain what.