I have found the paradox, that if you love until it hurts, there can be no more hurt, only more love...
There is no greater love without experiencing suffering. Love that is smooth as a silk is not eternal. But a love that experiences rough sailing endures. God's love is eternal but He has to endure great sufferings in order to express that love. Same thing is expected from us.
If we want to give a love that is unconditional, we have to cross the bridge that is under siege. We have to sail our boat amidst turbulent waters. We have to overcome the pain and do sacrifices in order to express this so called undying love for others.
Do not be afraid to love. It is better to suffer and love than not to love at all. For it is in loving that we can experience the fullness of our life.