The Pack by Jason Starr (2011)
I'm 3/4 through this book and it's been fun so far. It's an interesting take on the werewolf genre.
Here's the premise:
Simon Burns gets fired from his job without warning, takes on the job of stay-at-home dad for his 3 year old son, and is in a strained marriage. Things start changing for him when he meets a "pack" of stay-at-home dads at the park.
I think you can figure out where it might go from there...