Will not take meds anymore

My husband and I have been married for 7 years, together for 11. We've known about his ADHD since he was 25 (he's 31 now). We've had our share of rough times and things are better than they were (No longer considering divorce) and we love each other very much but I know that there are parts of our relationship that are out of control. I know that because of the ADHD some issues are just 'time bombs' waiting to go off and send us back to that place where we can't stand each other. 

I won't go into detail about the issues, I'm sure they're like your own. He is very high-functioning at work and very successful in his career so he doesn't think he needs the meds since he "got the equivalent of a college degree in aviation on his own with out meds" as he loves to point out. HOWEVER he has been on medication before (for a little over a year) and he KNOWS that they, to quote him, "make him a better husband, father and employee"....so....why won't he take them? He says because they make him feel sick to his stomach. I suggested trying another med/dosage but he won't hear of it and goes back to the "college degree on his own" thing.

The thing I'm really concerned about is that we have a 4yr old a 1 year old and one more baby due in a couple months and he (although he refuses to recognize it) isn't up to taking care of them without meds.He is a super loving father but he is too impulsive (taking our DD, then 2, to play in the river in 40 degree weather) or neglectful (forgetting to feed the kids for hours if I'm not there to remind him) Since I'm now a stay at home mom I can prevent a lot of his symptoms from affecting the kids but it's exhausting to have to 'protect' them from him and it is damaging to our relationship to always have to nag him or tell him no so that the kids don't suffer from his impulsiveness, short-temper, or distractedness. How can I make him see that we need him to try his meds again?

Every time I point out the issues I mentioned he says "well, If I'm that bad you shouldn't be with me" classic manipulation, and then goes on to point out my faults to get me on the defensive. What should I do?