I am married but my wife lives in another country. I know my wife will not allow Mutah, so can I do so without her permission to avoid falling into sin?
Muslim married man is not allowed to do Mut'ah marriage with any woman from People of Book (Christians , Joes and Magi) with out permission from his Muslim wife.
You should try your best to travel to be with your wife at least once every four months, as it is not permissible to leave your young wife more that four months.
Wassalam.