It is often that love fails. It fails in the sense that it is driven back and there is no hope of success. Often you see an optimism that love always prevails, but the reality of scripture is that love does not always succeed.
Many of the prophets of God where driven back and failed in a sense as they taught love. They did not fail in their righteous living but love is often driven back by evil. God does not always allow love to prevail over evil in this life.
At times love may need a strategical retreat. You find a number of instances in the bible where the bible teaches that we should remove ourselves from situations rather than continue.
Love is an active power for good in the world, but we need to have wisdom. Love will not always prevail and at times love should retreat to a safe distance. There are hopeless battles and while we should not presuppose any battle is hopeless it can quickly become apparent that some battles cannot be won.
In the Christian life we often need to use wisdom or seek wisdom in prayer. At times attempted "love" that ignores the facts of situations can be more harmful than completely ignoring the situations present.