Fourgolds is right, if a little dramatic. Mixed sex sharing is illegal but I have never heard of anybody getting thrown in jail or deported for it- and I'm pretty sure it would make 7-Days (the local free paper). The authorities will turn a blind eye unless the situation is brought to their attention and then they can't ignore it any more. It does raise some interesting questions about visas and sponsorship though.
Same sex sharing is only illegal for villas- apartments can (for now) still be shared. Also, it is unlikely (although not impossible) that the authorities will be interested in (say) two or three expats sharing a 3 bedroom property- your landlord might not be too keen though. The rule was always there and has recently been more strictly enforced when it became apparent that villas with (literally) a hundred sub-continent labourers living in them were a fire and health hazard.
Basically the whole property rental situation is either a nightmare (sharing) or very expensive (living on your own). Or, sometimes, both.