I wonder if whatever this plan is has been the final straw for Jane and Steve? They were hanging around a lot not long ago after Aurora was born so if some fall out happened it was after that.
They could also have had words about them having another baby, either they knew there were no tubes tied, they didn't agree about rushing for a reversal or this whole "mistake" with the ligament happened earlier than they are saying so Jane and Steve were already aware. Whatever it is, they were hanging around a lot more than usual probably because they know Sarah and Chris are useless parents but have since not been seen or mentioned.