Vanity, revenge, loneliness, boredom, all apply: lust is one of the least of the reasons for promiscuity.
Boredom is often the cause of promiscuity, and always its result.
Youth is not enough. And love is not enough. And success is not enough. And, if we could achieve it, enough would not be enough.
At night, neurotics may toil not, but oh how they spin!
Self-confidence grows on trees, in other people's orchards.
Most of our diversions do not so much delay death as accustom us to it.