Insecurity can cause several problems in a relationship:
- "you have to love yourself before someone else can love you"
- You can project your insecurity onto the other person, and convince yourself that they don't like you. (this is particularly a problem if you're unaware of how insecure you are)
- It can (if unchecked) lead to emotionally abusing the other person, by putting your insecurities onto the other person.