BBM
I think SL is the source of that. Back at the beginning someone/a friend mentioned that she was looking for a waitress job.
If SL was the source of the rumour that she was considering going back into dancing, and assuming he knew then that this was untrue, he and his lawyer conjured this up to make ML look bad to the jury. If in fact she was looking for work (because SL was not working) and if she took on a waitressing job, then that would make her look good and SL look bad. SL did not want to look bad, so it does seem to fit his personality that he would make up this lie to help sway the sentiment of the jury away from ML.
Of course it has ZERO to do with what happened in their home that night, ZERO, but the jury system is filled with people, some with strong opinions, and sadly innuendo can affect the outcome.