Just to quantify AirNoServices advice
The school my kids go to costs around 26000 dirhams/year per child plus all the usual school stuff like uniforms, trips, activities etc. That is a primary school and not the most expensive, but not the cheapest either. Kids start school at 4 years old and the fees for a 4 year old are around 24000dhs i think. You can find plenty of cheap schools, but you aren't going to want to send your kids there.
The club membership for the family will cost anywhere up to 15000dhs, but mostly around 8-10,000
Accomodation varies wildly as does any where. The cheapest you are likely to get away with is around 35,000dhs. If you want bigger in a better location, you will be around the 70,000 if you want a villa in the traditional expat areas you will be well over 100,000.
On top of that, every holiday you take will be an overseas trip, which for 3 people adds up fairly quickly.
So, on 15,000 dirhams with a wife and kid and no allowances, you will live very poorly and save no money. With allowances you will live reasonable and save no money.