Well, okay, let's find the 'logic' behind love for some...
Illogically, love is an emotion, undefined. Logically, it's a telepathic contract by two individuals to stay together, as far as they can, as long as they can. However solitary you might love to be, Man is a social animal. Living alone kills him. And logically, it's much much much better to have the lifelong companionship of one person only, rather than the temporary camaraderie of a crowd.
Logically, it spares you from those Tarzan style arranged marriages where neither the bride knows the groom, nor vice versa. It's very hard for people to change, and at your own advantage that you get to know them well, very well, before you step in for a miles journey. Now, you may advocate friendship is an alternative, but no, it's not a substitute. A friend is and remains a friend. They do not share intimacy, nor the closeness you would find in a romantic relationship. Better the devil you know.
The world is a cruel place, competition strangles people. Everybody has his own goals to achieve, no time to care about others, especially strangers. You never know, who is a friend, and who, the snake in the grass, as common language puts it. Human behaviour is like this: without support, we often crack. Maybe you don't realize it now because you are well enclosed by your parents and family, but those who have none will tell. Anyway, you won't logically forever have the support of your parents.
Two people who engage together, and are there for each other, in every difficulty, who will pick up the thorns their way, and make life hell easier.
Think clearly. Why do you love your parents? Because they care for you the most in this world? Because they have been here with you, day, night, and will be in the future too? Because they relieve all your troubles and share in your joys?
If you love people, you love them for a reason.
=> Logic was here before love.
