Sentence:  In part, this is because it is impossible to know what the UK's <WSD>divorce bill</WSD> will be until the EU knows what the relationship looks likes after 2019: if the UK seeks to stay as a paying member within some programmes, for example, that would reduce the bill. 
Meaning of the word marked with <WSD> tags:  The payment to be given to the EU on the UK's exit of the European Union, estimated at around £39bn.