can she be cheating when shes drunk

many wimon will use the excuse that she doesnt remember the night before when that would be her excuse to get off the subject that she might have done something that night.

when she goes to a spot with no signal,when she wants to be alone when shes on the phone,when she deletes the text she recives and sends and says that it is a habbit

these are clearly signs u should be suspicous but u need to get hard facts before confronting them