1.
If you stick by someone, you continue to give them help or support.
...friends who stuck by me during the difficult times as Council Leader...
PHRASAL VERB : V P n
2.
If you stick by a promise, agreement, decision, or principle, you do what you said you would do, or do not change your mind.
But I made my decision then and stuck by it.
= stick to
PHRASAL VERB : V P n