Hello Hivers
insecurities and fear is in the mind of every relationship both young and old, asked myself several questions but came up with a few reasons.
Emotional Baggage(Negative past experience): Many of us have walked away from certain relationships either because of unfaithfulness, dishonest, lack of loyalty, commitment or perhaps it nature was just too toxic for comfort and as such we carry those negative feelings an they become part of us thereby making it difficult in subsequent relationships based on unresolved baggage.This creates the insecurities we end up projecting.
Confidence: we're only as secure in a relationship as we allow ourselves to be because some of us lack confidence in what we can do or how we look based on being constantly told you weren't good enough, getting teased and bullied in school or perhaps even the lack of proper affection growing up. All these experiences would definitely have long term implications on a person and if Left unresolved,will continue into adulthood or for a life time.
Fear of the unknown:I believe anything perceived as precious to someone, there also comes the fear of loosing it. A person who has financial issues, insecure attachment style would probably end up showing fears in obvious ways. They could get jealous easily, extremely sensitive, constantly seeking validation from you because they feel threatened by anything that could pull their partner's attention away.