Weak in the mechanism of resilience
Depression is the flaw in love
If you were married to someone and thought "Well, if my wife dies I'll find another one," it wouldn't be love as we know it. There is no such thing as love without the anticipation of loss, and that specter of despair can be the engine of intimacy.
No matter what we do, we're all going to die in the end. There can be no true communion between two human beings- each of us is trapped in our own bodies.