stick to (something)
Definition: to continue to do what you have decided to do, even if you no longer want to, or other people don’t want you to.
(This phrasal verb has more than one meaning)
E.g.1: The problem with making New Year’s Resolutions is that very few people stick to them.
E.g.2: It was very difficult to stick to the diet, especially when my friends offered me chocolates.
This phrasal verb can’t be separated.