Final answer:
A controlling partner displays behavior such as checking messages without permission, monitoring whereabouts, and attempting to control their partner's actions. This behavior is indicative of an unhealthy and controlling relationship.
Step-by-step explanation:
A controlling partner exhibits behavior that includes checking their partner's phone/messages without permission, keeping track of their partner's whereabouts and social interactions, and attempting to dictate what their partner can and cannot do. These are signs of an unhealthy and controlling relationship, which can have detrimental effects on the individual's well-being. It is important for individuals in such relationships to seek support and resources to address the issue.