I'm sorry that you are going through such a frustrating time. I think there are some things to look at deeper here and some ways avoid future conflict that you haven't considered yet. There is hope on the horizon!

First of all, I would really consider seeing a therapist (a psychologist) for yourself so that you can take care of your mental health state while dealing with so many frustrations, dissapointments, and anger. You must take steps in taking care of yourself first, or you will be entirely ineffective in dealing with someone else's problems (your husband's or someone else's) Have you considered seeing a psychologist for yourself?

Secondly---I have never heard of a doctor doing what you described above in determining if a patient has ADHD. For all you really know, he could quite possibly have something entirely different, such as Bipolar Disorder; maybe even something co-morbid even (which is more the rule than the exception in previously undiagnosed adults with ADHD).

I have also never heard of a General Practitioner (be they Internal Medicine or Family Practice) diagnose ADHD. ADHD is very complicated and it's symptoms can mimic a myriad of other similar disorders. There could also be something else going on entirely, or co-morbidly as I pointed out before. Stratterra usually isn't as effective in treating ADHD symptoms as a stimulant class drug would be. Stimulants come in short, medium, and long-acting formulas, and there are many different types of stimulants. They are usually the most effective in dealing with ADHD. Stratterra also does not work right away the way that stimulants do.

You also need to make sure that your husband sees a psychologist (not a psychiatrist or other counselor or doctor) who has experience in diagnosing and treating the adult ADHD population. They are far more skilled in the diagnostic neuropsychological tests that are used to aid in diagnosis of ADHD, and they won't just be looking at prescribing drugs as the sole treatment or sole goal of the diagnostic process. They will rule out other disorders in the process, and they spend more time in diagnosing than any psychiatrist or other M.D. would.

If they psychologist thinks a trial of a stimulant or other medication is needed, he can refer your husband to a M.D./psychiatrist whose clinical judgment he respects (or even a M.D. or psychiatrist of your choice) in order to see if they concur with his assesment for a trial of a stimulant drug. I am also a big believer of psychotherapy in conjunction with medication for treatment of ADHD, and research has shown that this approach is usually the most beneficial (as long as the therapist has skill and background with the adult ADHD population). He can work on his behavioral problems with the therapist.

He really should have his own checking account anyway, but you should keep yours separate. In that way, he can learn to be more responsible with his money, and it won't affect your account at all. If you wanted, you could have one checking account you share (with a smaller balance in it), and each have your own separate checking accounts. I would never let him dip into savings to buy anything at all unless it was urgently necessary for the both of you to begin with (but then you shouldn't either, IMO), as then you won't be able to save very much. Needs vs. wants are something that many people have to struggle with in our consumer oriented society.

You should go over his checkbook with him and make a time certain every day and/or week to review the bills and teach him how to make a habit of balancing his checkbook properly with every check written. The other option is to commit all bills due to online automatic drafts from his and your checking account. Then, the only checks he would write would be to non-bill items. If you do that route, you would still need to go over the checkbook with him at least weekly and reinforce good banking skills in him. He might never have learned the proper way.

I find it not too uncommon that males in general often overlook anniversaries, and that is not specific to ADHD. Even some females. I'm sure that he probably felt bad for overlooking it, didn't he? The question of getting a card or not alongside your birthday present of cake and ice cream seems to be a non-issue when you think about it. After all, he didn't forget your birthday, and just because he forgot a card isn't reason enough to be angry at him, don't you think? Maybe that is something of the perfectionism that you spoke of probably having too much of--getting in the way of enjoying the good things that he does do? Not accusing, just speculating.

What kind of hostility? Verbal? Physical? Either verbal or physical hostility is not to be tolerated in any relationship. If it is ever physical hostility, you need to call the police and get yourself safe right away. If it isn't violence toward you, but it is rather a heated argument, you must ask yourself if you are demanding too much too fast of him--if you begin an argument by accusing your partner of not doing what he is supposed to be doing, it will likely be perceived as an attack, and he will go on the defensive. You must learn to bring things to his attention in a way that isn't perceived as hostile. He will be much more receptive to whatever it is you have to say, and it won't blow up into something huge.

No one can remember things if they want to though---it isn't that easy. People don't choose to remember some things and forget other things. If he has ADHD, the thing to keep in mind is that one of the regions of the brain affected is the one that deals with the "working memory" and prioritization.

I certainly don't think doing things for him is a good idea. Teamwork is a good approach, but you really could undermine his confidence if you do it all for him. Is there a way you can do it with him and watch where he goes wrong at and show him the correct way?
I'm not sure what confrontational means in the context you've written it, but if you mean he argues with only you, it is likely because you live together, and he doesn't live with other people who are right there to point out his every flaw (even legitimate total screw-ups). He's probably quite bright if he can run his own business and make money at it. Your own description says he was quite successful in some business he had or was employed in before you married him. He just sounds like he needs some guidance.
I really hope that you encourage him to see a psychologist to get reassessed, and whether he goes or not, I suggest that you go to a separate one yourself to deal with the problems brought on by this dynamic. Patience goes a long way...take care of yourself.