How could I have been so stupid?
The Danish theologian Knud Ejler Løgstrup (1905–1981) famously argued that vulnerability lies at the center of human interactions, not only intimate ones, but all human interactions. You place yourself into the hands of others. This places an ethical demand on us when we interact with others. But, for Løgstrup, when we trust someone, we open ourselves up to the possibility that this trust will be betrayed. We do not expect to be betrayed of course, as Annette Baier puts it, but we are opening ourselves up to the possibility that it might happen. Løgstrup even says that when we trust someone, we surrender ourselves to the other. It may sound hyperbolic but I find it helpful, especially if you have been harmed by someone you trusted and think “How could I have been so stupid?”