It was Christmastime fireworks for Katy Perry and Russell Brand this year -- but not the good kind!
After planning to whisk her family via private jet to husband Brand's London hometown for the holidays, Perry, 27, changed course, opting to fly to Hawaii with friends.
"They had a massive fight," an insider tells Us Weekly. "She was like, 'F--k you. I'm going to do my own thing.' Russell replied, 'Fine, f--k you too.'"
Which explains why, come Dec. 25, the multi-platinum singer was snapped splashing in the Pacific Ocean off Kauai -- sans wedding ring. Meanwhil...