If we weren't born with a whole raft of behavioural stuff to support ingesting food we'd not be born at all. Surely it is even more so for love, don't you think?
When 13 was crossing the Atlantic he said people asked him how he coped with being alone and he'd reply one thing he did was to remember it wasn't going to last for ever. This rugged independent self-sufficient thing is a bit of a myth, I think. We are conversational creatures.
One of the main ways people cope is to talk to God. I remember the joke in my parent's generation was it's alright unless he starts talking back. but where's the fun in that! and where's the companionship where's the love and where's the justice if he doesn't talk back?
we could talk about endorphins but I just think we've got a lot more to learn about how it all happens. and talking endorphins peptides, cells and messengers is more likely to produce a limiting viewpoint rather than a full explanation of the religious experience.
we could talk soul mates, and I do believe, for all the mayhem and mishap, that there is a genuine experience underlying that idea. One thing we are learning more and more now we are getting older is there is a lot more to life than meets the eye. Tho funnily enough it is good observation that shows us that.