Love as Survival

As the ruling animal, the highest predator, in this world we have been naturally selected to death. Every tiny mechanism of our bodies being optimized to improve every generation ad infinitum, evolution in a constantly changing environment being, by definition, eternal. Our thumbs get agile, our brains grow, yet all is predicated on basic realities, one of the main ones is the fact that we die. Because we die there is an immensely powerful evolutionary drive to reproduce common to all living things, because all living things die eventually. The more complex the being, the more strategies available. Of these strategies, the higher level animal developed feelings directly linked to avoid death.
To survive, you must fear, doing so will make you fight or flee, all in the name of cheating death. Pain appears in order to let you know what to avoid in order not to die. A monkey mother's affection to her helpless children makes her protect them, to saved the species, just like the dog, the penguin and the woman. So emotions didn't spring out of the ether, the lot of them are survival strategies, including what we call "love", and it makes sense: protect your partner, whom your attracted to because they're your genetic complement who will create healthy children with you, and your future offspring born of that genetic bond will be also protected. Any human cultures that didn't do this were weeded out long ago. And now in our relative safety of the developed world, the marginalized importance of violent competition leaves love as the best weapon. Love is there for your survival, not enjoyment. But what if it starts to threaten not your survival but your happiness? Well at that time you'll have to half-gamble on what's truly important. For you that is, not your species, if you wish to, that is.