I think this is in an observational sense about as factual as one might get about love, but I also think it's a very narrow observation. Because truth is that in some ways it is inherently contradictory to the sentimentality of love.

It's intuitive to look at some kind of risk-reward mechanism of neurochemistry, but truth is that the most authentic cultural and historic iterations of love are the most unrewarding. It comes from suffering, and sacrifice, and more often than not acting against one's emotions.

If it was purely a matter of brain chemistry and emotional responses, then we'd all be quite cynical as a species, simply treating partners as empty tools or vessels to get high, and when people do that we call it an abusive relationship.

One thing that always stuck with me on the matter was Zizek's quote, saying "If you know why you love someone, then you do not truly love them."

And I think that's true. The moment you find a purpose, or a reason, or some practical gain behind love, then you're in a transactional relationship which is contingent upon expectations of reciprocation, suddenly it becomes conditional. A kind of contract.

True love rather I think comes from the characteristics of tragedy. What you do when there is nothing on the menu but despair, pain, decline and misery, whether you stick around or move on. To love is to share suffering, anyone can be happy when life is easy.

Personally for instance the last time I knew I was in love wasn't when I was happy, it was when I found myself performing very arduous tasks in order to care for someone with a chronic disability whilst living in poverty.

I could've just gone for a pack of cigarettes and never returned, but I didn't. Instead I would do nursing in the day, and stealing food at night, and most emotional responses I felt was fear, worry and exhaustion.