The "I" stands alone. There is nothing along with it. The "I" represents the "i" of your individuality. It's your ego, your identity. It is separate. It can't merge with the universe. The "I" cannot mix. So, it needs to assert itself. It talks only about itself. Due to this it often feels isolated. The "I" stands alone.
The "I" could have been written as "AAI" or "AI" in the English language. But it was not. Because "I" is singular, there is no duality or multiplicity. Ego is your self-identity. Nothing else can go along with it. So, "I" stands alone.
"I" is selfish. Because it looks inwards towards itself. It fails to appreciate anything other or outward. The selfishness of "I" is the cause of its pain.
To remove pain, "I" needs to be destroyed. The original, selfish "I" was very protective. It could not tolerate hurt to its ego. The new form has destroyed its ego. It no more has anything to defend or protect. It is now a free spirit. It can assume any form now, other than "I". This form can merge, unite, and combine. From a singular it has now the potential to liberate itself into an universal. There is no solitude now. Only freedom.