do you want to say that beside private key that I am holding for my address there is around this number private keys that will resolve into my address or something else?
Yes.
if that is a fact, I really did not know that, but that does not seems as a good thing, is it?
It depends what you mean "as a good thing". Brute forcing 2
160 is an insanely huge number. Even if 2
256 is of course 2
96 times 2
160, which is even bigger, it is crazy to think that you can find one of those 2
96. So saying that 2
160 is less secure than 2
256 is like saying that it's safer to keep your money on Pluto, rather than Mars. Both cannot be stolen, they are considered untouchable from any person.