Someone sounds a little bitter.
Love definitely exists in the world. I'd go as far as to say it is the only real thing in the world. Most of reality is a relative perception based from the observer to the subject, and thus, it is difficult to agree on most things.
However, regarding Love, people across time and space concur that it is the most powerful motivating factor they've ever experienced.
That being said, Psychology shows us that there are many barriers built around our psyche in early stages of development that can impede our ability to live a healthy emotional existence.
Although, if you define Love as "being married" or "having sex" or some other ephemeral quality of the relationship between two humans... you're going to run into problems around the semantics of Love.
Do some reading on it; it's a very complicated subject that goes much deeper than any summarization could do it justice.
Are you chasing after a Love that is perfect, unchanging, and unconditional? You may need a god to fill that role ;-)
Or can you accept a Love that is imperfect, changing, and conditional? That's the kind we Humans can handle along with the goal of reaching the Ideal Love means that we will evolve our own concepts on Love so we are always treating others and ourselves with our most up-to-date idea of Love.
If you want a proof of Love, it is a simple matter of finding it's negative: Hate. Hate's not hard to find in the world, so just look where it doesn't exist and you'll have a good idea of Love. Mother Theresa, Ghandi, Jesus, and Bhudda all gave pretty good life-long examples of what Love can help a person achieve in a life time. The tough part is sorting through the miles of crap that have been appended to their lives and seeing what were their real messages.