Are you self-employed? That can be a way to bump your income significantly in the belgian IT world. My email is in my profile if you want to talk about it. (self-employed for 5 years, 1 kid, early thirties, also in Belgium)
The taxes are a bit high but have a lot of benefits of living in Belgium. But it is true that you have to make some compromises/sacrifices if you want to make your disposable income stretch.