A relationship is work.

Absolutely. And it’s an oath is just a commitment to work at it, and not just throw up hands at the earliest opportunity

There is no right to the rest of someone’s life on either side should they change their mind or evolve in different directions;

It’s not a “a right to another’s life” it’s a commitment to a shared life. And yes, that commitment can not work out, which is why divorce is now thankfully pretty easy.

that is slavery

Not using any common definition of the word, no.

I have no right to stop them. This is true equality and freedom. It is a fundamental human right.

See, divorce - above. Some marriages don’t work out, or are abusive. That doesn’t mean there’s no value in marriage.