There are various reasons why people could have relationship difficulties. Sometimes one might feel lonely despite being surrounded by people. There could be other reasons why someone could find themselves not feeling supported, not feeling confident and feel different to others. Sometimes people find it difficult to connect to others and when in a relationship they find it difficult to maintain the relationship over time.
Individuals differ and there are lots of contributing factors that give rise to different personalities.
Understanding your self is the first step to building a healthy relationship