I'd imagine that all pharaohs are bisexual because the gods would never make Mutotanosa have to be with someone he/she couldn't love. I think that the same-sex marriage is always primarily for love because the pharaoh needs a great deal of companionship while their opposite-sex spouse and one or more of their children are gone for weeks at a time, representing the throne around Orina Anoris.
Can you imagine Kudorin without a spouse by his side for that long, able to interact intimately only with his belas? All Anorians love him because he is their Pharaoh and their god, one of the Seven Siblings. His belas are like that, too, as evidenced by the fact that most of them trained as priests before entering bela training. But the purpose of Anosukinom is having a ruler who is both man and god and the needs of the man are just as important as the needs of the god. He needs a constant stream of affection, sex, love, and companionship from someone who loves him for him, not because he's a god. Also, his spouses remain his spouses after his divinity leaves him and goes to their eldest child, so they need to be cool with him not being divine anymore. We saw how Anorik was affectionate with Manosuta as well as with Eleita. I'd imagine that Anorik's marriages grew stronger as many long-term exceptional marriages tend to do regardless of whether she was Anosukinom or Anorik.
Anikira fell in love with Kudorin as a man, continues to love him as a god, and will love him just the same when he is no longer Anosukinom. Xio Voe, I think, was awed by the god and loves Anosukinom as he loves the Soracic gods, albeit more directly, but he kind of accidentally fell in love with Kudorin in the process. I love that part.