False.
Fulfillment anxiety is typically associated with feelings of unease or dissatisfaction with one's own life or accomplishments, and is not directly related to concerns about a partner's fidelity. However, it is possible that someone experiencing fulfillment anxiety may project their own insecurities onto their relationship and become overly suspicious or jealous of their partner, which could lead them to believe their partner is being unfaithful. It's important to address these feelings and communicate openly with your partner in order to maintain a healthy relationship.