Army Cohesion is a Concept in Mount&Blade II: Bannerlord.
Official Description[]
The Army Cohesion stat represents how motivated your army leaders are and how well they work together. Armies start with 100 cohesion and it drops each day the army stays in the field, depending on how many leaders are in the army. When Army Cohesion gets low, non-player leaders could leave the army. At 0 Army Cohesion, the army is automatically disbanded. Sometimes army leaders replenish their Army Cohesion to 100 when it reaches 0, in order to keep the army operational.
When the player is the army leader, cohesion can be increased in increments of 10 at the cost of influence points.