/facepalm
Let me see if I can explain this.
Back in 1965, there was a stage play called "The Odd Couple", which featured one neat/neurotic room-mate and one slovenly/sloppy room-mate. The entire idea was that the neat one brought order to the other's life, while the slovely one brought fun to the neat one's life.
But they WEREN'T GAY.
Neither is Starsky and Hutch (though David Soul is), Xena and Gabrielle, Fonz and Richie, Laverne and Shirley, Barney and Fred, Ren and Stimpy or Batman and Robin.
They just aren't.
It doesn't matter how much slash shipping and decreements you make about how it would be "better". They aren't. And making them that way would not only hurt the characters, but show that a character's sexuality is dependent on the prevailing thoughts of the time.
This. Is. Wrong.
No matter how you roll that particular dice. Equally, Will and Grace will not get it off, because he's gay and she's a woman.
Like many other shows, we also have to bring in the very basic idea that THEY ARE PUPPETS.
They do not have a sexuality because they don't have sex. They just don't. Get over it.
They don't even have a viable gender. It's like the cretinous idea of making the Cookie Monster eat healthy food.
HE'S A MONSTER THAT EATS COOKIES. IF YOU REMOVE COOKIES FROM HIS DIET, HE DIES.
Do you want to kill the Cookie Monster? Do you? Do you really want that on you conscience?
Bert and Ernie are muppets. They are not male. They do not have sex. Therefore they are not and cannot be gay. Let alone married.
Leave them alone. Ernie's never going to leave Duckie anyway.