I may not see the future but I've seen its lonely architect.

Holding their partner’s unconscious/dead body

Sobbing into their partner’s shoulder/chest

One of them is hurt and the other falls asleep in their hospital room

The other losing their mind when their partner is hurt/killed and charging into battle recklessly

“I thought I lost you” hugs

“Don’t go where I can’t follow!” 

One is mind controlled and forced to fight the other

The other refusing to harm them and getting seriously injured as consequence 

The person coming to and seeing what they’ve done

I could go on about this trope alone for 5 hours

A last desperate “I love you!” 

A tearful, hard kiss before battle, bonus points if its a confessional kiss

“Please, I don’t know what I’d do without you.” 

Bandaging each other’s wounds