Where to begin? Annoyance. I was annoyed by all the italicized words. (I'm perfectly capable of using the correct emphasis as I read.) I was annoyed by all the brief, inconsequential jumps into the future ("so and so would go on to do such and such") that seemed less like intriguing foreshadowing and more like pointless, truncated rabbit trails. The story loses immediacy that way. And, erm, I was annoyed by all of the parenthetical asides. (I mean, who would do that in a novel?) I was even annoyed by the title, which I will explain later.
And then--beyond my annoyance with the writing style--I didn't really like any of the characters, or even believe in most of them. Quite a few of them seemed amorphous in my mind; I couldn't picture them, and didn't have a firm grasp of their personalities or mannerisms. I guess it's debatable whether that's Irving's fault or mine.
Finally, at times the plot felt so aimless and meandering that I decided Irving must be one of those authors who just "waits to see what the characters will do" as he writes. So it was really weird to read in the author interview at the end of the book that I was completely wrong. He basically plans his novels out in minute detail before writing them. He told his characters exactly what to do in every situation, not the other way around. So I don't know why the book seemed to have a weird "Hmm, let's see what happens next" structure. Not to mention the fact that the plot doesn't feel nicely balanced; in the first part, the two characters who I would have considered the main characters end up being of little consequence in the rest of the book.
The weirdest thing of all is that, despite all of my complaints, I didn't hate this book or find it boring or dread picking it up to read it. It certainly never reached critical mass, and I obviously didn't love it, but I've read much worse. The first part focuses on an affair between 39-year-old Marion and her husband's 16-year-old assistant, Eddie; the rest of the book is taken over by Marion's daughter Ruth, who was a child in the first part but is a grown woman during the remainder. Marion, Eddie, Ruth, AND Marion's husband/Ruth's father Ted are all writers (which was another little tidbit I found hard to believe).
And as for why I found the title annoying: it's a nice title, but it doesn't really exemplify the book the way a title should. Yes, Ruth does end up being a widow for one year (which happens after she publishes a novel by that title), but the book hardly touches on that year--it's certainly not about Ruth's year as a widow.