At present there are 28 EU member states of which only 9 of them are net contributors. The UK is the second largest contributor after Germany. Of course the EU does not want us to leave, we pay in far too much for what we in return get out of it.
At present we buy more from the EU than the EU buys from us. Of course the EU does not want us to leave, we are one of their best customers.
We leave with "No deal" and we trade with the rest of the world. This releases us from the current tariffs that the EU applies to goods coming from outside the EU. We are free to negotiate our own deals in order to purchase elsewhere what we used to buy from the EU - who are the EU member states going to sell the produce and goods that the UK used to buy to? We leave with "No Deal" and we wave goodbye to about 26 billion (UK's share of what the EU hold but have not yet spent) but we save at least 11 billion a year (A figure that had we remained in the EU would have increased year on year) and we are not saddled with some bill where the figure has just been plucked from thin air without justification or substantiation. Of course the EU does not want us to leave, what a dangerous precedent we would set for their remaining members.