While it is nice when parents contribute to weddings, it should not be expected. Also would you want this guy to contribute as he seems likely to be the person who would hold it over you. You should be lead by your future wife if she wants rid of him support her, if she wants a relationship with him support her, if she wants therapy to deal with the past support her. If you feel you can not support her then no you shouldn't marry her, for her sake as well as yours. You don't have to be a 'rescuer' to support some one