No, marriage is not worse than prison, unless you happen to be this particular seventy year old bank robber. Marriage is a union of two loving people, while prison is a punishment for wrongdoings. To compare the two is to insult one of the most wonderful institutions in the world.
I do not think that marriage is worse than prison. Marriage is something that should bring together two people who already love one another. If they decide that they no longer love one another then they should end that marriage via divorce, not choose prison by committing crime and getting arrested.
Marriage is not worse than a prison sentence. Even in a bad marriage, there are ways to get out of it, including separating and divorce, In the even of abuse, where the spouse feels like a prisoner, there are alternatives such as safe houses. There are choices one can make in a marriage that are not available to prisoners.
No, the marriage usually isn't worse than prison, but it all depends on the person you chose to marry. There are many marriages that are build on the shaky foundations, by the people that didn't know each other well before marriage. They usually end up in divorce, or the people involved start hating each other and turn their marriage int something worse than prison.