I am non-EU citizen (Bosnian) but my wife is. We permanently reside in an EU country and want to visit UK as tourists. Do we both need a visa to enter UK? Or is it only me who needs a visa as non-EU citizen?
The UK has left the EU, so your wife no longer benefits from free movement rights when traveling to the UK and you no longer benefit from free movement rights when traveling to the UK with her.
Citizens of all EU countries can currently travel to the UK for tourism, business and some other activities without a visa or other advanced authorization*.
You on the other hand are not so lucky, as a Bosnian citizen you would need a Visa to travel to the UK.
* The UK is planning to introduce an electronic authorization system similar to the US ESTA or Canadian ETA. It's still several years away though even assuming the government delivers it on schedule.