Should I get a second Xbox 360?

My girlfriend and I have been living together for about a year now for a little over a year now. She is supportive of almost everything I do but I feel I need another Xbox 360 and she is totally against it. It's not like I want it just to be petty, its because she plays my 360 just as much as I do and now her brother has recently moved in with us and plays it all the time too. My big problem is that I am a hardcore gamer and I do play tournaments with cash payouts and I've had to drop out of a few tournaments already this year because I felt I didn't have enough time to practice