It's Complicated

Admittedly, this movie is aimed at the over 40 crowd. So no wonder I liked it. But I watched it with two of my sons, and they both appreciated it as well. The story is that a divorced couple, who have three children, all of them now leaving home, flirt with an affair. And what happens.
The couple are in their late 50's (nice to see Alec Baldwin playing a character who is older than his stated age), who are in New York for their son's college graduation, first share a drink, then several more, and one thing leads to another until whoops, they are in bed. He is glowing. She is vomiting. Which largely sums up how they continue to view the liaison.
Meryl Streep has tremendous capacity as an actress, and she is able to convey the nuance of what she is struggling with in this film--yes, she is enjoying sex, and yes, she is enjoying it with her ex-husband. And while she is very clearly sleeping with a married man, she has slept with him more than his current wife has--which only makes it familiar, not exactly okay, but somehow she is ok with it until she realizes that she isn't. She loves being sexy to someone, but she is deeply unsettled by it being him.
There is a lot to quibble about with this movie, but there is also a lot to like, and I think the deconstruction of what might have gone wrong in their marriage is well written and also a good model for how to make things emotionally stable between two people who share immense amounts of a past and present with each other.