What is the ruling on affirming a marriage contract that includes an option clause (khiyar)?

Primary text

If a marriage includes a condition granting the option to either or both parties whenever they wish, it shall not be affirmed because they do not believe in its binding nature, unless they believe only the condition itself is void while the marriage remains perpetual. If the option was for a fixed duration and they embraced Islam during that duration, it is not affirmed for this reason. If the duration has passed, it is affirmed because they believe in its binding nature.