My wife and I watched It's Complicated the other night (another one I'd had on the shelf for a while). I have to admit, I was rather disappointed.
The scenes with just Steve Martin, Alec Baldwin, and Meryl Streep were generally pretty good (and sometimes excellent), but the chemistry with the rest of the cast, especially the kids, just wasn't there. All of their interactions seemed forced (except, I now remember, for the one scene in the bathroom with the son-in-law). Actually, Baldwin's acting sometimes felt forced, as well (I still say that the only really good thing I've seen him in was The Marrying Man).
I feel like I should have something deep to say about this, being the child of divorced parents, but I really don't. I wonder if I would have, if I'd had any siblings. Hard to say.
I don't think I'd have been freaked out if my parents had done something like that, though. More likely, I'd have been happy for them. Although I'd have probably been even more upset at the end of the movie, I think. I certainly wished, for many years, that my parents would get back together.
Overall, I guess I'd rate it as an ok movie. It definitely had some hilarious moments, but that was more than balanced out by the rest of the movie. As I said, a bit disappointing.