Is it ok that I never swear?

Sure it's OK. The less you swear the better for you. Keep up the good work ! Like Corey said, it does just come out sometimes but it's a matter of restraint. It's not only OK not to swear but really great that you don't !

Of course it's OK. Well done.

Swearing is natural and a convenient way to blow off your emotions. When the three wise men visited the stable to see the baby Jesus, don't you suppose that if they'd trodden, barefoot, on a rusty horseshoe nail that they'd have said something excremental?

But habitual swearing is boring and it's a sign of a good vocabulary that you can express yourself adequately without resorting to bad language.