While I agree with Donald, I would like to add that the overarching problem with relationships – in fact in everything – is simply sin.
Selfishness has its root in sin. In the Garden, Adam and Eve sinned by deciding to take what God had consecrated as holy because it looked good, was desirable for obtaining wisdom, and was edible. And ever since then, we have been bent in that same manner – choosing to Impress, Indulge, and Increase our posessions as we try to portray our own “godhood” (little “g”), make ourselves happy, and create our own little piece of heaven.
And the result of sin was God’s curse on the earth. Consequently, everything that once was exactly the way God wanted it became broken. Nothing works as it was intended. And God did this for the good of greater things to come (Romans 8:20).
A broken world-system coupled with our selfishness provides fertile ground for misunderstanding. God help us to lay ourselves and our agendas aside as we partner with him to bring peace on earth and good will towards all mankind.