This is a common belief it seems. But I thought long and hard about... even did a good amount of historical research ... and evolution does not support "falling in love"... rather it's the opposite.A product of evolution. Humans, and all other animals, jump through all kinds of hoops for sex. It’s the prime directive for animals.
Looking at it from the male side, the most effective way to spread your genes is through violence and rape. Conquest and war. Kill the men and children, rape and enslave the women of child bearing age. Maybe this hasn't been so common in recent history, particularly the enslavement part, but killing and rape were certainly rampant during WW2... on all sides.
And as recently as medieval times we got the whole shebang. DNA testing has revealed 8% of men alive today from the region of the Mongol Empire ~800 years ago, are direct descendants of one man, probably Ghengis Khan. That's the most extreme "recent" instance, but there have been similar cases then and earlier. Further back in the Neolithic period (~8k years ago) the genetic diversity of men dropped to the equivalent of 1 for every 17 women... and that was world wide! It was the dawn of civilization, and larger and more advanced groups built their "empires" through killing, rape, and enslavement.
Falling in love has no part in any of that.
Even when looking at normal familial relationships that we are accustomed to, "falling in love and marrying" is a very recent paradigm. Throughout history in nearly every civilization or tribe we know of, arranged marriages were the norm, and people were expected to stay married for life. Falling in love was rightly seen as a poor reason to get married. Falling in love with someone else after marriage was likely to get you in big trouble and even killed.
The interesting question is why falling in love persists even when it is so contrary to evolution...? The answer must be that the belief in "everything is evolution" must be wrong... and for those who still remember what it is like to fall in love, and have fully surrendered to the experince and have not been jaded by disappointment... ya, it's wonderful. Just amazing. Glad to live in a time and place where this is possible or even common. There are many things in the world that are like this if you look.