We are naturally wired biologically to desire attachment to others. Learning how to attach to others begins from the day we are born. We begin learning from birth about attachment and how relationships work through the interactions and care we receive from our primary caregiver (usually mom or dad).
The attachment of an infant to parent (or caregiver) can have a lasting impact on an individual and their adult relationships. Our relationships in infancy can have a profound affect on our future relationships because of what we learned in our earliest relationships.
When insecure attachment takes place during infancy and childhood, this can wreak havoc on adult relationships. Problems such as abuse, clinging to abusers, low self esteem, control issues, jealousy, emotional dependency, and relationship paranoia can become prevalent when insecure attachment in infancy/childhood affects adult relationships.
Not to fear though; there are many individuals who have experienced insecure attachment in infancy and childhood and have healthy relationships in adulthood. The key is recognizing the behaviors that may stem from insecure attachment and learn how to handle them.