As far as I'm concerned he's innocent until proven guilty, but if it is true in any measure of what I've read it's disgusting. It's a low act to hit a woman, even lower to hit a pregnant one. And your girlfriend of all people.
The worst part is, if/when Lui gets the sack, that won't accomplish anything. He might spend a year or so in exodus or in the ESL but he'll come back to the NRL sooner rather than later with another club and the only loser in the Wests Tigers. I really feel for the club as well in a situation like this. Their reputation takes a battering, they lose their halfback and they gain absolutely nothing for taking a hard stance.
And in 2-3 years time we'll be reading stories about how great it is to see Robert Lui back in the NRL with Canberra/Manly/Parramatta/Newcastle/Melbourne etc. and how the how the Tigers should've done more to help him out.