I presume that this "cotidie" is a variant of "quotidie"? I still remember "Panem nostrum quotidianum da nobis hodie" from the prayers of my childhood -- my first exposure to Latin grammar!
Cotidie, cottidie, and quotidie are all seen -- most often, in modern editions, cotidie.
Same story for the adjective meaning 'daily': cotidianus, cottidianus, or quotidianus.
Why is "Tu cotidie matrem visitas" wrong?
It isn't wrong.