Wow that is exactly what it is!
Discussion
From a legal perspective, it's a violation of a contract. There should be penalties for violating a contract.
And said penalties should be determined by the contract (and thus, the contracting parties).
Marriage is more than contract, most religions would agree--but it is not less than a contract. The State is involved because property ownership is involved. In marriage, two become one "with all their worldly possessions." If there is a breach of that contract the property of the one must be divided into two again, and that means justice is called to mediate. If there are children, again, a division must be made fairly.
There are religious and moral ramifications to both marriage and divorce but those should be handled by church authorities. The civil aspects must be handled by some disinterestrd third party with enforcement power (whether that's a State or could be something else I'm not sure).