Is there a need of Nucleous in order for 2 masses to rotate around each other?

Answer 1

I think you mean at the atomic level, but still the answer is no.

One counter example would be positronium. This is when an electron and its anti particle, a positron, "revolve" around each other. This is very unstable with a half-life of about 10^-7 seconds.

There are other exotic atoms of this type. Any atom formed by a particle and its anti particle is called an onia.