Simple logic proves that Eternity is multiversal.
Eternity and Infinity represents time and space, Eternity represents time.
The relativity theory states that time is four dimensional.
Now the theory of parallel universes (which would be the only explanation to that there would be a multiverse, like represented in Marvel's case) states that the 4th dimension is an unlimited about of 3rd dimensional planes--just like counting with intergrals, you use a infinite amount of 1 dimensional lines to potray a 2 dimensional area.
Recap:
Eternity = Time = 4 Dimensional = An infinite amount of 3 dimensional universes = Multiverse