My grandfather, a WW1 vet, had 2 wives die on him (his first in her 30s after only a few years of marriage, his second, my grandmother, in her 40s, after 18 years of marriage) both of similar cancers. Though he continued to live his life by going to work, he pretty much spent the last 20 years of his life drinking himself to death, holding on just long enough for the birth of his only grandson (me). He never dated again.
I'm very sorry.
It is very hard to go on sometimes.
Don't loose hope.