If you are just now realizing that this is a problem you probably have a lot more issues in your parenting than just diapers. Suck it up and toughen up. Make the kid grow up. It's your job.
My 8 year still wears a diaper?
The best thing to do is to encourage the child to try to ease off of the diapers by rewarding him or her whenever the don't use the diaper and trade that for the toilet.