I think it depends on the therapist. I was never terminated for cancelling. Snow storm, sick, kid sick, car broke, delayed at work etc Life happens all the time

Now if you don’t return for a very long time, therapist might have to take a new client and might become unavailable. I had a therapist who was ok with occasional sessions as needed. But some might not be able to. I think you need to ask them directly what are their policies. I doubt you get terminated for missing two sessions but you should ask them