Do a basic search on the boards. Worst case scenario - you are discovered, arrested, jailed and deported.

All it takes is one nosey or disgruntled neighbour or colleague at work.

Do people do this? Yes. Are you willing to risk the consequences? Only you can decide.

And as QS pointed out - how is your partner going to stay here legally? If you are in company accomodation, everyone around you and your HR dept will be well aware of your (non) marital status. That is a big no-no for them as well.