I don't talk about this very often for obvious reasons, but I've lost a child.
Grief over losing a child is not entitlement, or weakness, or being spoiled. It's grief, as raw and human as it's always been.
It used to be normal for children to die in the mid-1800's-England. Something like 25% of children born didn't make it to their first birthday.
Today, that number is more like 0.34%.
I suspect the difference is that in the 1800's it happened a lot. You weren't the only one. You had people who were empathetic. Nearly any person you'd come in contact with likely had either experienced the same trauma, or loved people who had. That doesn't mean people didn't grieve over the loss. It just meant that living with the grief of a lost child was normal.
In "modern" times? If it happens to you, you're an outlier. Not only are you grieving the loss of your child, you're alone. No one you know has also lost a child. You're grieving the loss of potential, the legal garbage, insurance, funeral costs, you're doing it either with your partner, also grieving, or alone (or maybe worse, with a partner, but still "alone"). The amount of times you'll hear "I can't imagine what that must be like" help reinforce that feeling of being alone, because it's simply true. It's unimaginable. It was for me, and even having experienced it, still is.
Whether it's the 1800s or 2000's, humans are resilient. While losing a child often does lead to depression and divorce, we can heal from these things. We have an advantage over 1800s parents in that we have huge support networks that are no further away than our pockets that blow away whatever community support might have existed in the 1800s. Not to mention medicine and advances in our understanding of human psychology.
Grief isn't weakness. Grief is simply human.