Travs said "Sorry for the simplistic view of politics... but...

How can they not vote this deal though, but then (likely) still give her a vote of confidence tonight..."

To understand this you have to first realise that the MP's have a free vote as the "deal" is in place because of a Referendum, not a Conservative directive. So Tory MP's can vote against the deal without it being seen as voting against their party. Of course, non of them would vote for no confidence and Corbyn knows it. He's between a rock and hard place because he knows a vote of no confidence is a waste of time but equally would be seen to be weak if he did not call for one.