By Google, I assume that you mean Google Chrome browser.
Both Chrome, Firefox, Opera, Internet Explorer and Edge will always forget your navigation history if you are using the private navigation feature. It's by design and can't be changed.
During a private cession, the cookies also won't get saved, meaning that you can not use any automatic login feature and viewing options offered by many sites will always revert to the default on your next visit.
Make sure that you don't use that feature.
In Firefox, click the Hamburger button (the 3 stacked lines) and click «Options».
Select «Private life».
Under the «History» header, chose: «Keep history» or the personalized option. DO NOT chose «Never keep history»
Make sure that «Clear history on exit» is NOT checked.
Apart from that, you don't have any easy way to change how long the history is kept.
In Opera, History is always kept for about a month, or never is using Private Browsing. You don't have more control than that.
Chrome is pretty much the same as Opera.
Just remember to NOT use private browsing if you want to keep your history.
Other browsers also have something similar, somewhere.
Electro, May 2017
