My two major life sadnesses were discovering the man I was going to marry was cheating on me (turns out he 'forgot' to mention he was bi and quite liked men too) and then losing my mum very suddenly to a heart attack.
Both were life altering/life shattering events but somehow, I'm still here and still breathing. As others have said, it sounds cliched but the process of time is life's greatest healer.
When I discovered the infidelity, I remember feeling like a piece of my heart was physically broken, like I'd never recover. These days I rarely think of him and I am SO thankful for my fortunate escape.
As for my mum, that's a different situation entirely but my feelings over her loss have gradually shifted from abject horror/devastation to being able to painfully process it all.
In the beginning, I could hardly bear the pain...now I carry it in a side pocket (if that makes sense).
To me, it's 100% like a wound on your physical body. At first it hurts unbelievably and you need loads of painkillers but then little by little, you see your skin start to stitch together and it hurts a little less. Then you get a scab and eventually the scab falls off and leaves a scar. The scar will probably always hurt but not as much as the wound did at the beginning.
Everyone's journey is unique to them but time will help.