The first cut is the deepest: Why we never forget our first loves

I was seventeen the first time I fell in love. 

It was with one of my childhood friends and we had what I now know was chemistry (at the time he was just constantly getting under my skin).

But when we started going out, everything clicked into place.

We fell into an all-consuming type of love, the only type you can have when you're 17.

It was the messaging under the covers at night/hungry kisses in my hall on a school night/naive and hormone-fuelled kinda thing. 

Being a teenager in general, your world is small and that means that everything is heightened.

This person is suddenly your whole life and because it's the first time you're having these feelings…it's intense. 

Things like jealousy rear their ugly head for the first time and this can cause dizzying heights and crashing lows.

When the inevitable heartbreak came, we were nineteen.

My whole world blurred and temporarily nothing seemed to make sense.

Being with your first love is a magical time and one that many of us just can't seem to let go of – but why?

Why do we have this bond?

So, this is the science bit.

When two people first meet, their bodies release a stress hormone called norepinephrine.

This is what makes you have the butterflies in your stomach, heart pounding away in your chest, the whole works. 

Researchers at Arizona State University College also found this cool thing – the hormone makes events burn into your memory.

You know the way you can remember specific kisses or conversations you had but what happened the day before is a blur?

They discovered a link that causes these strong emotions to form a specific sensory experience. 

In other words, when you get around that person again, their presence causes those old memories and initial feelings to come flooding back.

It's not that you don't forget about them; when you see them again, those old feelings of first love can return.

So it looks like first love is the deepest – in a literal sense as it's carved out what you think love should look like.

We never learn as much from a relationship as we do from our first serious one and because of that, they will never fully leave us. 

In the words of writer Daphne du Maurier, ''I am glad it cannot happen twice, the fever of first love. For it is a fever, and a burden, too, whatever the poets may say."