My late partner wanted to include my 2 sons in his will, to inherit if I predeceased him, but nothing to their mother. He knew them all slightly.
Stupidly, we procrastinated on having our wills drawn, and when he died following rapid onset of dementia, making him legally incompetent overnight, his old will was still in effect, which didn't mention me. But his estate was modest, not a great loss to me, and I did get to keep his personal effects.
When my present partner & I got together we had our wills drawn up within weeks, motivated by my previous mistake of not acting promptly. This time, my partner chose to specifically exclude my sons while naming me his primary heir, making instead his family and his oldest friends to inherit if I die before him. I've assured him I'll offer most of his things to his family & friends anyway, especially photos and other personal mementos.
In my will, he's my sole primary heir, while my sons only receive my personal effects if he predeceases me, everything else going to my partner's family. We also had other documents drawn to protect ourselves as a gay couple in Florida, which saved us much grief during a medical emergency not 4 weeks ago.