Control AC using FET
Run your simulation and check the power dissipation of the various components - according to a quick check (although I am not familiar with this simulator) I noticed your resistors are dissipating around 11W at peak voltage, and the MOSFETs at least 20W (you would need to check the safe operating area carefully if you plan on operating like this)
So unless you are planning some serious resistors, I think a rethink is probably necessary. The circuir will probably dissipate more power than the fan it's controlling.
Also be aware that 230V is the RMS value, the peaks will be 1.41 times that, ~325V. It seems you have set your AC source to 230V peak to peak. 

Why do you want to avoid switching?