Again you can not stretch unless there is room to stretch. By saying the universe is stretching, expanding, or getting bigger\smaller begs the question that if the universe is already infinite then how can it expand.
You are mistaking the difference between stretching and expanding.
Expansion requires more volume of nothing constantly to accommodate the new space.
Stretching does not add volume to space. What it may gain in length will be depleted in width for example, so no extra nothing is required for the space to fit into.
But complications in theories about space and time are throwing our research off track somewhat. Space and time is the most simple thing. Relativity is not just something I consider when thinking about Albert's theories. The relative size of space and time in my mind is of great importance. Consider that scaled up by incalculable quantities the stars and planets are a set of atoms and electrons and we will find many correlations between the infinite and the microscopic. So then again if we were to be scaled down to the size of 1/1,000,000,000th of a quark would it be possible for us to terraform an electron and evolve on it sustaining life from the power of our atom?
There is quite possibly no end to our universe, but even if there was there would be another universe right next door. I suspect it is a matter of scale and relative size/time blow into proportions that our size group will never be able to grow large enough to understand. Consider that in the time it takes a human to jump into a puddle of water, countless eons of existence may pass should there be anything small enough to exist within the universe that puddle creates on a scale we can never see. As the person lands in that puddle it kickstarts untold catastrophic events within the puddle universe. Yet for those in that puddle the splash would be a whirling cloud of atoms far above thier tiny electron that would be known as the stars and would take an almost infinite amount of time to 'splash' bringing the destruction of the universe. If people lived in that size dimension on a particularly furry and wet electron they called earth they would stare at their puddle splashing for the whole of their existence marveling at the colours and vast size of it all but perhaps never find the edge.
That is all we are, no matter if the puddle analogy could be true or not. Our infinite universe is a mere splash in time and we live far too quickly and on far too small a scale to ever see the big picture. Even if we travelled out of our puddle into the next we would be unaware we had left and indeed, if there are 'people' living at a relative time and size that is so vast that we are as invisible as what makes up an electron to them, we will never be discovered. Our whole universe will be born, will live and will expire in the blink of an eye to these giants as they watch a drop of rain fall from the sky and into their hand. It is not even really a factor of size that truly blinds us to what existence is even
if something is so small or large as to make the size of our universe seem more reasonable. The problem is time, we cannot live fast enough to see what is tiny and we cannot live slow enough to see what is so big.
