Love occurs with laxity.
... You know how they derive statements as in "what you love destroys you, etc" or in life "you hate the people you love, etc".
What I'm saying is, those are just a petty excuses - when a person starts to love someone or something, it's a sign that he/she is being negligent of a particular belief/value system, or duty. Therefore (presumably), he/she is already in that state of negligence, which can be used as an excuse to 'self-destruct' having not gone higher for a purpose, or something. To sum it up, love is and always will be something 'personal' to a person - not going beyond a universal meaning for it, and it can neither be subjected as being 'innocent' nor 'guilty'... it's entirely how the individual 'sees' it.
... And that can happen at any time, has no particular 'origin' because as we've come to know - we are (naturally) quite selfish and arrogant creatures. Should love exist, I'd think it would exist in the context that I've given - it's around being self-centered.