Why the hell is
this question even being asked? And why the hell are they framing it as a sex thing?
Of course children's shows should include queer characters. And it has absolutely nothing to do with sex.
Even very small kids understand the concept of romantic love. They understand the concept of liking someone so much you want to spend the rest of your life with them. They understand that grown-ups pair off, get married, share a house, raise kids, etc.
Yes, sexual attraction plays a part in these pairings, but it's hardly the sum total, and that's the case whether the couple in question is opposite or same-sex.
If it's OK for kids to see Cinderella finding her prince, then it's OK for kids to see a prince whose idea of happily ever after includes another prince.