The title characters of The Ren & Stimpy Show are the spitting image of the stereotypical 1950s husband and wife, with Stimpy as the fussy housewife and Ren as the exasperated "working stiff", Ren delivering frequent Domestic Abuse to an absolutely submissive Stimpy (unless the episode required something different), and the both of them sleeping in the same bed.
This song is more than enough to know there's something going on, with lines like "I've never asked for anything, just your happiness" or "And just once, when you strike that pose, could you think of me?".
Despite the subject of Ren and Stimpy being more than friends appearing as a harmless joke in the original show, the Adult Party Cartoon series, though not official, explicitly confirmed it.
"Son of Stimpy": A distraught Stimpy is at the door calling for his "son" Stinky. Ren tries to get him inside to decorate the tree, then points up at the mistletoe hanging over the door, bites his lip and coyly bats his eyelashes. Stimpy screams "That's all you can THINK OF!" in response. Yeah, that's not even trying to hide it.
In this same episode, when Stimpy's "son" introduces his fiancÚ to Stimpy and Ren. They are holding each others, and sing "Memoriiiiiies".
The amount of times Stimpy orders Ren to open his mouth in that episode is highly disturbing. Granted he's Ren's nurse, but the mischevous/enthusiastic expressions he puts on while doing that encourages further implications (to those whose minds choose to go into the gutter). The medicine taking scene is really exaggerated, with making the spoon REALLY huge and Ren mentioning that "that's some icky-tasting stuff!" (had Ren mentioned that it was medicine, then it wouldn't have been so risque) and the countless Double Entendres ("Now, swallow every little drop! Isn't it tasty?").