A man sits in a restuarant crying as a waiter pours him a glass of wine. The waiter asks, "What is the problem? Is something wrong with your wine?" The man replies that the wine is fine. His wife then says it's their twenty-fifth wedding anniversary, and she's spent the whole day trying to get her husband out of bed. The man starts crying again, and the woman angrily says, "Why did I end up marrying a guy like him?" She storms out of the restuarant. The waiter asks what happened on day the two should be celebrating.
The man launches into a story about the events on their fifth wedding anniversary. The wife berates her husband for not making enough money. She orders him to go out and work more so that she can have money to buy diamond earrings. The husband replies that he thought she wanted to go away somewhere for their anniversary, so he took time off work. The wife says she hates men who make excuses. The man angrily replies that she spends all his money on gifts for herself and the young man she's seeing. The wife retorts that a real man lets his wife spend money how she wants. She leaves in a huff.
The husband, tired of the abuse, goes to a lawyer and says he is thinking about killing his wife. He asks the lawyer how long would he be locked up for. The lawyer tells him twenty years. The man decides not to kill his wife.
The waiter replies that it was a wise decision. The man becomes hysterical and shouts "Are you kidding? Twenty years, and I still haven't been set free!" Obviously, the punchline is that being in a marriage is equivalent to being in prison.