This is worst case scenario, bro. If you've truly been doing nothing wrong and she's acting all suspicious like this, either she's been stepping out, or she's losing her mind and getting crazy paranoid. Start protecting yourself now. Give all your money and assets to your brother, father, mother. Talk about getting some counseling if you love her and want to save the relationship. Unfortunately, she's at risk of turning on you, whether you like it or not and whether you've done anything wrong or not.
Be careful, and I hope it all works out for the best.