Why does H+ ion always get associated with other atoms or molecules?

The reason why any atom or molecule is formed is because the ionic forms cannot remain stable.

When H⁺ ion is formed, the size of the ion is very small (near about 10^-3 pm. The normal atomic and ionic sizes vary from 50 to 230pm. Due to which, it cannot exist freely and it has to be always associated with other atoms or molecules to get stability.