I guess there's no fast and hard rule to know when it is considered that it is love. It's a feeling more than anything else. I don't try to rationalise these things, as what they say is true -
love knows no reason.
Romantic love? Well. If it is love towards a partner, it is always romantic love - is it not? Love is quite broad and the most defined word. I think love is of different levels and different kinds i.e., filial love, love for a best friend, love for a sister/brother, etc.
So when people
fall out of love - I guess this is when they don't feel the same way anymore and either do not want to reconcile their feelings anymore. Or, they found someone else to love.
And when you're
in love, I guess you just know it. It's a feeling like no other.