You have to put in so much effort to look big that it just does not happen by accident. If you just want to lose the belly all you have to do is stop eating. No exercise required. Resume eating when your body finishes eating the belly.
I don't want my body to eat up my muscle mass in the process.
You really don't have to worry about accidentally building too much muscle. It takes a ridiculous effort. I'm talking about multiple hours of training a day, 6 days a week. If you go and spend an hour in the gym lifting weights 3x a week and do some cardio before each session, you'll get a nicely shaped body with well defined muscles but you definitely aren't going to be even close to looking like Ronnie Coleman, trust me.
With "eat up" I was talking about losing muscle by not doing any exercise while I'm on a caloric deficit :)
Make sure you're getting enough protein and do some weight training while you're cutting and you shouldn't really lose much, if any, muscle.