Essentially he had left his wife over 3 and a half years ago to be with his GF.
GF is pushing him to get a divorce and finalise everything. Ex is not agreeing to a divorce. He does not want to get married again and he has had this conversation with GF and she accepts this but still wants him to finalise divorce.
He has offered cash incentive to wife to agree to divorce ( this was the bit she didn't know ) but she still refuses.
I said for the sake of another 18 months why don't you just leave it and then apply for a divorce yourself as they will have been separated 5 years. That ways saves money, is simples to do and will cause much less grief.
That is the bit GF is not happy about