“Is love an invention created by humans?”
I think love is a concept that humans have thought up more than an invention. In the rest of the animal kingdom, only some animals have a life partner. Most species have a season when they find someone to mate with, but that is just because of instinct and they may not be together for more than one season. Some creatures even eat each other after mating. Even domestics dogs and cats will breed off a one or two-night stand. The idea of ‘love’ as we know it is just something we have created to make reproducing sound more meaningful.