I voted no, for several reasons.
1, The U.K. government is the Conservative & Unionist party. They are supposed to support the union.
2, The Queen is 94, and I cannot imagine any U.K. government allowing any possibility for the break-up of the U.K. during her lifetime. For the same reason, I don’t think there will be another Scottish independence referendum in her lifetime.
3, The Irish govt know that NI is an economic basket case which is heavily reliant on the support of the U.K. govt. They wouldn’t want to be in the position In which West Germany found itself in 1991, with crippling reunification costs to bear.