Anyone under 45 would find this film a bit 'iffy'.
They most probably, had never served in the armed forces, & understand the relationship of serving men, in combat situations, or had a long long term loving relationship.
This a bit of a love story & of someone a bit old style 'bolshie'.
If told you can't - you carry on.
The flash backs? Fantastic, especially near the end. Anyone married (or in a partnership) for 40/70 plus years, will & can see their partner as they were when they first met - I do, when seeing my wife, after 45 years together.
If you don't shed a tear, whilst watching this , you have no heart or soul.