This is an ABC podcast.

The beginning of the end of Florence Williams' marriage came in the form of an email.

My husband and I had been married for 25 years, and one night he handed me his phone to see an email from his brother, only a different email came up.

And it was an email that he had written to another woman, suggesting that he was in love with her.

And that was the moment that I felt like my life suddenly changed.

There is never a good time to read a message like that, but this was a really bad time.

Yeah, we had friends about to walk through the door for dinner.

So, in fact, they did walk through the door just as I was looking at this email.

So it was terrible timing, and I couldn't, you know,

process it really or talk about it. But I was incredibly distraught and distracted. Yeah, I had to

plaster a smile on my face, you know, for a while.

You're listening to All In The Mind. I'm Sana Khadar.

If you're lucky enough to have fallen in love at some point in your life,

you've probably also had your heartbroken.

For science writer Florence Williams,

the experience was excruciating, protracted, and really confusing.

I had never experienced heartbreak before like that.

I was stunned by how much it hurt, you know, how low it took me.

And I was really surprised and sort of baffled by why I felt so much of the pain inside my body.

You know, my body was registering these emotions to the point where, you know, I wasn't sleeping.

I had these chest palpitations, stomach distress. And the more I learned about this,

the way that our immune systems actually change

...