Same situation here. My first language is Russian and i find myself using curse words more freely in English than I do in Russian. For some time it felt like following some kind of "double standard", but then I realized it has to do a lot with the differences in cultures and how it shapes the way we speak in different languages.
Words like "fucking" etc. are more engrained in everyday language and life in the English-speaking world and are used by mostly everyone. For instance, one of my professors who has a great sense of humour is known for dropping the f bomb during his lectures. This is always followed by the burst of laughter by us students. I cannot imagine the same situation and reaction happening with one of the Russian equivalents for F word if the university professor would use it publicly.
Russian curse words do sounds more rough and offensive to me, but I think it has to do with culture. I think there is a greater separation between the slang/curse language and "elevated" language in Russia than in the English-speaking world.