Relationships end, some break-ups are mutual with both people seeing the relationship as over. Other times one person is done and the other is not. This leads to grief over the loss of the relationship.
A lot of times we allow fear of social situations to control us. Be it public speaking, going to an event where you don’t know anyone, or just going out after work we all have some places where we are anxious in social settings. Even for the more outgoing and extroverted there are times when social fears and anxieties cause us to avoid interactions that otherwise would be to our benefit.