If our purpose in life is to have relationship, then, how should we live?
It's not that difficult a question to answer. God makes it pretty clear, throughout the Bible. It was summed up by Jesus thus - “Love the Lord your God with all your heart, soul, mind, and strength; and love your neighbour as yourself. This is the law and the prophets.” When you read the prophets, you realise he wasn't wrong. A constant refrain through them is “Act justly, love mercy, and walk humbly with your God.” Always it's about two things – how we relate to God, and how we relate to each other. Always, to act in love.
Notice one thing that it isn't about. We are not to concern ourselves with other people's relationships, whether with God or others. Our focus is to be on ourselves. For who are you to judge someone else’s servant? People cannot be forced to love, they must choose to do so. They cannot – and this is something that right-wing and left-wing politics fail miserably on – be forced to be good, to act in the right way towards either God or their neighbours. Or themselves. Human beings must be permitted to be miserly, and to bear the consequences of their decision to be such. If we attempt to coerce them to act otherwise, we ourselves are no longer acting in love.
Love God, love your neighbour. That's it. Like many things in life, it's not complex. It's just difficult, and impossible to do perfectly without the grace of God.