Which means all the States should have a say regarding whether a State may secede. The federal government must make sure the Constitution is obeyed. If the States permit the secession, the feds should not interfere. If the State block the secession, the feds should enforce that decision.
So if you decide to divorce your spouse you can’t unless the spouse agrees? Ok.
That’s not how contracts work. Besides, several states (including VA and NY) included clauses in their ratification of the constitution that provided for secession if they deemed the constitutional contract to be broken.