First, something I found by renefrost:

if you love him more when he's away than when he is with you, it's not love -- it's lonliness.

if you love him more when he is with you than when he is away, it's not love -- it's lust.

if you are a better person (more capable, more at peace, better at your job, better at dealing with your family and friends, better at driving) and like yourself more since you've been in this relationship, it's love.

Later, update.