JANE GREEN: I know what my cancer has done to my husband – and my heart breaks for William. After Diana’s devastating death, Harry estranged, Charles ill, and now Kate’s shock diagnosis – how utterly alone he must feel

Finally, the world can stop speculating and coming up with countless fantastic conspiracy theories or tasteless ‘jokes’ about what happened to Kate Middleton.

I’m sure there are plenty of people who were embarrassed when the news broke of her cancer diagnosis on Friday. But the one person I think of in all of this, the one person my heart goes out to in every way, is Prince William.

This poor man.

From his parents’ divorce when he was just ten years old, to their subsequent divorce, quickly followed by the untimely death of his adoring, adored mother, we have witnessed time and time again how life threw hardships at him.

In recent years he has dealt with increasing disagreements with his only sibling Harry and sister-in-law Meghan, his father’s cancer, and now this – an unexpected and tragic burden on top of everything else.

The distance from Harry is undoubtedly felt particularly keenly.

In recent years he has faced increasing disagreements with his only sibling Harry and sister-in-law Meghan, most recently his father’s cancer, and now this – an unexpected and tragic burden on top of everything else.

After all, he’s the only person who fully understands what this is like. The only person to have endured both divorce and the death of a parent, in such a devastating public setting, is irreconcilably estranged.

There were certainly too many stones thrown, too much pain and too many injuries for Harry to provide any comfort or strength to William.

William who now carries the weight of the crown as his 75-year-old father undergoes his own treatment for cancer; William must support his young family like never before.

As someone who has danced with cancer myself, I know how overwhelming it is for your partner. My husband was terrified when I was diagnosed with malignant melanoma in 2014, much more terrified, he later told me, than I seemed.

Our children were 14, 13 and the twins were 11. While everyone gathered around me, few thought to contact my husband.

He stepped in to care for the children, driving them back and forth, making sure their lives continued to progress normally, all the while worrying about what might happen to me.

When friends called him, they asked about me, and like William, he bore much of the burden alone, putting on a brave face, knowing he had to be strong for all of us.

We now know that the prince pulled out of his godfather King Constantine’s memorial service at 11am last month because he had just heard of Kate’s cancer. Two days later he was back at work and showed tremendous courage and devotion to duty.

We will hear endless speculation about Kate in the coming days, but few think about the partners and everything they have to go through when their loved one is struck by a serious illness.

William’s pain is even deeper right now considering his three young children: George, 10, Charlotte, 8, and Louis, just 5.

They are not much younger than William was when his mother died, and that trauma and grief, the specific fear of losing a mother, is undoubtedly something he will bend heaven and earth to protect them.

We don’t have a prognosis for Kate. She says that she is receiving preventive chemotherapy, that she feels ‘good’ and is ‘getting stronger every day’. We are all thinking of her and praying.

But illness is a great equalizer.

The distance from Harry is undoubtedly felt particularly keenly. After all, he’s the only person who fully understands what this is like. The only person to have endured both divorce and the death of a parent, in such a devastating public setting, is irreconcilably estranged.

There were certainly too many stones thrown, too much pain and too many injuries for Harry to provide any comfort or strength to William.

William’s pain right now is even deeper considering his three young children: George, 10, Charlotte, 8, and Louis, just 5. They are not much younger than William was when his mother died, and that trauma and grief, the specific fear of losing a mother is undoubtedly something he will bend heaven and earth to protect.

No matter how much help the Waleses have, how many nannies or nurses there are, William must now be a steadfast force for his children and wife.

And while Kate may need space to break down, to lie awake at night with fear dancing around her head, William will feel like he needs to be a rock, as all partners must do when their loved ones are so seriously affected are.

This is as much William’s struggle as it is Kate’s, but he, as stoic and kind in public as his mother always was, will now be under pressure to keep that mask on at home too.

No matter how scared he is, he can’t show it.

He has to keep smiling for the children and reassure them that mommy will be fine.

Children are remarkably observant: if he lets his fears surface, they will notice them, so he must keep it all deeply hidden while surrounding them with the safety, security, and love they need right now.

He is not only a husband, a father and a prince; his main role at this time is caregiver.

Whatever your life revolved around – family, work, charities, royal garden parties – everything stops when hospitals and doctors take over your daily life.

Considering everything William has been through in his life, we can only hope that he has trusted friends and loved ones to care for him as well.

They need to let him know that no matter how stoic he has to be for Kate and their children, he needs to know that he can crack, to let out that scared fifteen-year-old boy who just lost his mother.