Frustration With Spouse for Not Holding a Job

How do you deal with an ADHD husband that can't/won't hold down a job? I have been the breadwinner for the duration of our marriage (13 years) and realize I have enabled him to "do his own thing" without concern about helping to support our family. He has held a couple of jobs for more than 2 years and he also likes to start his own businesses, but in either case when he runs into difficulties or has conflicts with others, he jumps ship. I know I've allowed this to go on for a long time, so how do I start dealing with this or is it too late?