The Wallcreeper by Nell Zink:
He warned me that his parents were arty. His father sat me down on the dock behind their house and advised me to enter into a suicide pact effective on Stephen’s fiftieth birthday. I said, “If I make it that long,” which was the right answer. His mother didn’t make it home that weekend. We were married in Orphans’ Court. From the vault to the altar took three weeks. We didn’t talk much about what we were doing. We had a deal.