Is there another habitable planet in our galaxy? I have wondered, what'll happen when we destroy our planet or it becomes uninhabitable for human life? Is there another option than the complete extinction of the human race? Can anyone give me a logical response?
what'll happen when we destroy our planet or it becomes none-habitual for human life?


Very pessimistic idea.

We lack the technology to tell if a planet orbiting another star could be lived on by humans.  We barely have the technology to detect some planets orbiting a small number of other stars (compared to the number of stars in the galaxy).

The term for these planets is exoplanet and Wikipedia says we have detected about 3750 to date orbiting about 2800 stars.  As there are somewhere between 100 and 400 billion stars in the galaxy, we only know a tiny fraction of what's out there.

We have a very limited basis for listing some planets as possible candidates for supporting some form of life, but, with all respect to the serious scientists doing this work, this is nowhere near knowing if they really can support life at all, let alone humans.

So your question's answer is : we don't know.

We cannot travel fast or far enough at present to reach another star in a reasonable time frame and we also could not do it with enough people.  We do not currently have any reasonable expectation that we will be able to do that in the future.

So even if we knew of a suitable planet, it would be unlikely we could ever travel there to e.g. colonize it.

So we're stuck here so keep recycling. :-)