This should be easy for someone to remember.
It was possibly made in 2009-2010, set in an isolated seaside town in New York. The wife thinks her husband is cheating on her but he's really taking acting classes and ashamed to admit it.
I thought the husband was De Niro, but I can't recognize the movie name in his filmography.
Further clues that may contain spoilers below:
Parents thought the daughter was at college but she was stripping. Teenage son had a fetish for fat women. Wife went to cheat on her husband because she thought he was cheating on her.