"Men don't want to hear 'you should,' 'you have to,' 'you always,' or 'you never,'" says Florence Isaacs, coauthor of When the Man You Love Is Ill: Doing Your Best for Your Partner Without Losing Yourself (Da Capo Press). "You've got to make him feel like he's the one deciding, not that it's you shoving this down his throat."
Also, don't make it about your needs. "'Do this for me' is a lousy motivator," says Steven Jonas, M.D., professor of preventive medicine at Stony Brook University's School of Medicine on Long Island. "They have got to make changes for themselves."
But be clear that you're willing to facilitate. Tell him you're all for taking nightly walks, preparing healthier foods, and adjusting your schedule if he needs more free time.