Few of us go into marriage with the intention of divorcing, and in that sense it is a "failure." Besides, marriage is the most important relationship we make out of choice. My view is that it represents a "failure" to maintain and sustain a promise made.
Promise, schmomise.
We make promises based on a particular set of circumstances.
In the past I've worked with women in violent marriages. They so often say "I can't leave him because I love him – and I’m married to him – and I promised to stay with him through the good times and the bad” Should they keep that promise?
Or … I’ve got an Uncle who was a priest. Amazing man. He had a lifelong passion to contribute to development work in the third world and joined the priesthood because he claimed to have a “vocation” but also because I think he thought it would be a good way to work with vulnerable people in developing countries. His Order had a policy shift and they pulled out of all their Missions. His passion for his work was so great, at significant personal cost and public embarrassment he left the priesthood. He now runs an orphanage of 5000 children in India. He broke his promise to God and the Church institution … but I don’t think he considers himself a failure. I consider him a brave hero with immense personal integrity.
Is it really right to keep a promise for the sake of the promise? I don’t know about that.