You are having fistula in ano/ sinus. A empty space around 1.2 x 0.4mm is there next to the anal canal. So the watery discharge is present from that space.
You may require a minor surgery to open up the space and clean it, so that it closes completely.
You need to be examined by a general surgeon to evaluate further.
Life style modification is needed with increased fiber in diet and water intake.
Next Steps
Lifestyle modification and a clinical examination.
Health Tips
Sitz bath( place your bottom in warm water)