As to why He always appears as a couple? The first question.
This being the Ramayan forum, let's take the couple "Sita-Ram."
Any other couple from the previous post,
"Lakshmi-Narayan, Uma-Maheshwar, Gauri-Shankar, Radha-Krishna, Rukmini-Dwarkadheesh"
too could have been taken, it makes absolutely no difference.