Just came across LDP's Twitter (edited to include it above) that seems to support he's not in every single episode. Either they worked around him like they did RDA in his last seasons, or he's left back on Earth is my guess.

Personally, I don't trust this particular set of TPTB to handle any relationship correctly, het or gay. They are too ham-handed and don't seem to understand any form of subtle behaviors or characterizations.