And also control when they get out.
The Constitution does not have such rules. Does that mean you cannot ever get out? Wouldn't that seem like tyranny? Look at the 10th Amendment. The states have rights which are not enumerated. Is the right of secession discussed? No. It is an unenumerated right. Which means, according to the 10th Amendment, that this is a right which is reserved to the states.
Getting into the union is a joint decision by both parties. But getting out ought to be something a state can choose to do by itself.