"always" is an adverb of frequency and so usually, the present simple is the correct tense (like in this sentence!). However, the present continuous form has a special feeling about it when used with "always". It's used to indicate frustration or disappointment and the use of "always" is exaggerated e.g. "When I come home from work, my wife is always watching soap operas. I just don't understand what she likes about them!" "My husband is always watching football. It's just a group of men kicking a ball around!"