Possible Clues:

• That steed will give you no peace
• Henpeck like old horse
• The sort of horse that will keep going on and on
• Annoy the old horse persistently
• Scold; horse
• Henpeck, scold non-stop
• Bettor's interest
• Back seat driver, e.g.
• Horse; keep scolding
• Complaint suffered by horse