• freed, loosed, separated
• if something comes unstuck, it becomes separated from the thing that it was attached to.
• if a plan or system comes unstuck, it fails; an informal expression.
• if someone comes unstuck, they fail badly with what they are trying to achieve; an informal expression.
• break down, fall apart (e.g., "it is so unfortunate, their marriage came unstuck after only a year and a half")