Not unusual. Males keep getting bigger, and maybe his ego has grown too. Tank size stayed the same I assume.
Tank size... the longer the tank the further the females get get out of his way. What size tank?
Tank community... are there other fish in the tank? A crowd of fish can provide distraction. What fish are in the tank?
What can you do? Not much. Get a bigger tank, might help. Get more Red Empress females, may or may not help. Add other fish to be a distraction. Keep the water temp under 80F may keep him more mild, or not. Replace the male with a younger male.