Not only any other Dom/Domme, but any other person, period. Ferrets and cats, I'll allow.
To the TS, I am a dom and I am not polyamorous at all. I didn't get into this to have a harem- rather, I focus all of my energy on the fulfillment and care of my dear pet.
I can't imagine burning that brightly for multiple women at the same time. My girl radiates through the unpartitioned whole of my life.