NOOh, ok. Just curious. Thanks anyway!
ROFL you guys - well it was short and to the point eh?!
I agree that maybe both those types of love mentioned by bebu are instinctual, bearing in mind that there are other animals besides humans which pair for life.
Whether they evolved raises for me a question of when evolution began. I'm thinking that the desire for procreation must have existed from the start otherwise whatever organisms there were would have died out as quickly as they came into existed. So, is 'love' in its various forms 'built in' rather than evolved?