Roissy "Heartiste" says on his blog, in a post titled The Sixteen Commandments of Poon,

VII. Always keep two in the kitty

Never allow yourself to be a “kept man”. A man with options is a man without need. It builds confidence and encourages boldness with women if there is another woman, a safety net, to catch you in case you slip and risk a breakup, divorce, or a lost prospect, leading to loneliness and a grinding dry spell. A woman knows once she has slept with a man she has abdicated a measure of her power; when she has fallen in love with him she has surrendered nearly all of it. But love is ephemeral and with time she may rediscover her power and threaten to leave you. It is her final trump card. Withdrawing all her love and all her body in an instant will rend your soul if you are faced with contemplating the empty abyss alone. Knowing there is another you can turn to for affection will fortify your will and satisfy your manhood.

Does "having options" mean sleeping with multiple women?

What is Seddit's opinion on Cheating? (I'd always thought of PUA guys as "good guy greg" rather than complete douchebag assholes.)