Sometimes, we like to be alone, even if we're the bubbliest most sociable people in the world, solitude becomes a necessity at times, it's a self cleansing system of sorts, one's mind recharges with deep thought, and deep thought is only reached in solitude, it's quite amazing how a mental action is best executed with a physical action.
You reach great decisions in solitude, if you think a little bit about your own greatest decisions you'll be surprised to find that those most probably were taken after a day or night of solitude. Your senses are fine tuned to your own thoughts when you give all your attention to you, even if the decision is to seize your solitude; proposing to someone or accepting a proposal.
You're at your most transparent state when in solitude, so any mental attempt to play a game of strategy is void of its purpose, all the roles you play around people are removed from their element like you remove a coat when you reach home; the intellect, the considerate..etc, all the social "masks" are taken off, and you're left with the real you, the one only you know, with all your flaws, all your vices, the ones you always make sure to hide when not alone.
Its funny how when you're in love, you tend to want to be alone, away from people, and with one thought, about one person. Solitude becomes your destination, you intentionally go through that mental trip, and when you reach that certain "Nirvana", you willfully decide that your solitude is a pilgrimage for your love, a proof of your devotion, it's not a coincidence that we have only one heart and one mind! Longing too is an act of solitude, when you miss, your surroundings seize, you can't feel the people around, your soul is somewhere else, with someone else.
lovers don't finally meet somewhere, they're in each other all along.