Convincing hubby to change his mind for #4

Hi all just after some advice on how to change hubbys mind on having another baby. Im feeling the need to have just one more but he seams to think its going to be too hard taking a new born camping ect. We took #3 camping at 6 weeks old so we've done it before. I do all the nappy changes and feeding and 99% of the care ect. Please any suggestions.