Here's a specific answer to number 2, because it's trivial: structure your business founding contracts and documents accordingly. Make sure there are clauses for vesting or share distribution that reflect what you'd find acceptable with respect to effort delivered. These documents can be as detailed and fine-grained as you like, down to the minute if you're especially motivated/masochistic.
For the first question, I have a few suggestions, probably that you will not find appealing.
First, do try some introspection, especially with a view toward truly analyzing whether "driving hard": a) means what you think it means (in the specific context of your projects) and b) is a working solution for you to accomplish your goals--I'm loathe to invoke canned/cliched nonsense, but sometimes "work smarter, not harder" actually does apply; c) is something you would do regardless (that is, are you the kind of person who wants to solve a problem, or are you more after the thrill of "driving hard" in and of itself, and so no matter what your partner(s) might do, you're going to drive that much harder).
Second, seriously consider the possibility that what you need is an assistant/employee and not a co-founder. That is, consider that the breadth and depth of the projects you're interested in, with respect to the real size of the problem and the amount of effort necessary to produce the solution, just aren't as "big" as you think they are. It may be that the problems you're solving are solvable by "one person plus a little help", and don't need more than one person "driving hard." In this case, since you seem to enjoy "driving hard," you're looking for the wrong kind of partnership: you want somebody to pass off parts of the project to, but you still want to control the overwhelming majority of development.
Third, seriously stop and think a moment about your statement regarding how demanding "the business aspects" are. I'm going to be viciously blunt here: your question reads like you have a real ego problem and, unfortunately, at the same time somewhat ironically that you lack the understanding that "the business aspects" are actually meaningful if you want to have a "big" success (for certain values of "big"). Getting them done is not trivial, and certainly can be at least as demanding as the technical components of a product. That's intentionally vague because, frankly, your question is (we don't know what you consider a "big problem" is, what "good money" means, etc.). You're "doing fine financially" as a "developer/entrepreneur," so that is an indication you have at least some idea of what the non-technical "business aspects" of this industry are. Maybe you should try to study them so you have a more mature understanding, and therefore are less inclined to be so utterly dismissive of non-technical co-founders.