If you want to keep your teeth straight then yes you will need to wear your retainer for your entire life.
If you decide not to wear the retainer anymore then your teeth which once again eventually shift and become crooked again.
So if you want to keep your teeth straight with the retainer then you must wear the retainer the rest of your life.
However if you do not want to wear the retainer anymore for the rest of your life then you certainly can remove the retainer and not wear it anymore.
There's nothing stopping you or forcing you to keep the retainer in your mouth the rest of your life but if you want your teeth to remain the same with the retainer then you must wear the retainer for the rest of your life.
I got tired of wearing my retainer eventually and no longer wear it anymore and my teeth have shifted again but I don't care.
I just couldn't stand wearing the retainer anymore.