When you want someone to be the person you could be drawn to, and wish that by their entering your life, your life would become more worthy of living, it is INFATUATION.
Difference is subtle, but not very difficult to make out for those who understand themselves well.
The most exciting, yet fulfilling phase of a relationship is when it is part love, and part, infatuation.
And no, it need not be definitely with someone of the opposite gender. :)