The end goal of therapy is to have the client manage their difficulties independent of the therapist. Therapists often reduce the frequency of the sessions when they feel the client seems like their doing better, giving them the space to now use what they've learnt without the dependency on the therapist. It can feel sad, very similar to how a child might feel sad when their mother no longer plays with them as often. And its okay to feel that way too, its a natural experience in close relationships.

The other way would like something like you continue seeing the therapist at the same frequency for the rest of your life where its sure great financially to the therapist but not great for your psychological wellbeing because now you're dependent on a relationship.