Actually it's bonding. From an evolutionary perspective it's important in our species for a few reasons. Familial love ensures that your family, who are your only absolute allies, will be those allies. And romantic love secures a partner with whom you can produce high-quality offspring.

Someone asked a question about love, and how it's experienced a few weeks ago, and I think that answer will show you why it's inherited and why it's so important for our species and others.

Is it truly an option in most species to love another in a romantic sense?

I can tell you that with this question the answer is no. The vast majority of species don't form pair-bonds. If the question was "Is it an option in some species?", then the answer is yes! In some species it's absolutely necessary for successful reproduction, and at least the mammals that have that option are probably having a very similar emotional experience to us. Their pair-bonding rituals activate the same kinds of neurotransmitters and pleasure centers in the brain. So most do not love, but those that do probably love just like we do (if not more).

Does it exist in an objective sense?

That really depends on how you want to define love. If you want to define it in the romanticized sense that we're taught through stories and culture, where two people fall in love and never fall out of it, then the answer is a guarded yes. But it may be rare. The human mating system is really fuzzy because we have cultural constraints that vary widely, but it seems that largely we would be best called serial-monogamists, meaning that if left to their own devices and not constrained by culture or child-rearing or some other external factor, most people would fall in love with a few different people in their lifetime.
But that doesn't make it any less real. Ultimately everything you experience is your brain taking in signals from the world around itself and trying to make sense of things. In the case of very powerful emotions like love your brain has a massive response; so big that the emotions can overwhelm you in the short term, and permanently alter your brain in the long term.
So I guess the answer is that love is what you want it to be. Either it's just brain chemistry tricking you into raising children with another capable person. Or it's an extremely powerful emotional attachment to the person you've chosen to spend your life with that will enrich both of your lives and bring you the most joy knowable for as long as you mutually decide to let it.
It really is both at once.