DNF at over halfway - SPOILERS

The plot idea behind this book is good. It's really interesting, but as it is used in this book, it doesn't quite work. Possible spoilers, though I will try to keep it non-spoilerish.
The book opens with a couple on a first date, talking about how, since they are smart, they could get away with killing someone. Then we jump to years later where said couple -Will and Nat (short for Natalie) are married with a young son and the marriage might not be doing well. Nat is a bit too anal and Will might be having an affair.
And then Nat finds out that her son has been molested. Since she is a defense attorney, she knows what children go though when questioned, so she decides to kill the pedophile. But Will has to step in at the last minute to clean up the mess.
And that's part of the problem - if I am suppose to believable that Will is willing to back his wife up, I have to buy that he has some type of feeling for her. And I just don't buy it. The reader is shown a first date and then a marriage that is a degree of trouble. There is no in between. There is mention of happy times, but since we don't really see them working as a couple, it's hard to fully buy Will not caving.
Nat too is a problem, mostly because she seems too judgmental and superior to those women around her. In fairness, this could be a comment on suburban women who have one rule for themselves and another for everyone else. But you don't even feel intense dislike for her. Unlikable characters are fine, but you should feel something.
Finally, there is too much repetition. The author tells you the same thing more than once, and most times it sounds like an info dump.