My sincere sympathy Saetana.
How anybody “copes” will vary from person to person, day to day and is not a linear progression .
It’s not something we can ever prepare for -even those whose partners may have a terminal disease, and nobody who has not been in your situation however well meaning can fully understand.
Take it one day at a time. If you have a couple of supportive friends (my best friend came with me to register DH’s death and then took me to a Garden Centre for a HUGE slice of cake and a coffee) that can help.
Don’t be afraid to reach out, phone a friend, have a weep or go out for a walk and shout out all the anger you may be feeling.
It does get easier (4 years on) but it’s like an amputation- you learn to limp but you may never feel completely “whole “ again.
I still have flashbacks and regularly cry myself to sleep but nobody would guess.
It’s a cliché, but be kind to yourself. 
