Me and My partner Switch roles when drunk.

Im not sure why this happens but after me(24M) and my wife(24F) have had a few drinks we always end up reversing roles, i am usually VERY dominant and she is usually VERY submissive and i just wonder if anyone can help enlighten us as to why this happens? We've been on a googling mission but can't find any information as to why this might happen, it stlll feels good for the both of us, its just strange.