When I go shopping I do not put cash on the counter and then ask what the shop might have that I would like in return for my money. I ask to see the goods, enquire about the price and then decide whether to buy.I only produce the money when we have agreed the whole transaction, and as the shop releases the goods.
The EU wants the UK to shop the wrong way round. They expect us to put up a lot of money without telling us what it buys, and then keeping us in the dark for too long about whether we might get anything for the cash. They have invented a rule that they cannot reach an Agreement with us on our Future Partnership until we have left, which is most unhelpful and does not seem to be based on the strict letter of Treaty law.
Looking at the draft Withdrawal Agreement it is difficult to see why we would want to sign that, and certainly not without knowing what if any Free Trade Agreement will be reached. It will need considerable amendment, especially over the borders and freedom of movement issues. As it commits us to making a large financial contribution it must not be signed before we have an Agreement on all matters which is fairer to the UK than this one sided interim production.