@Jessa,
How does he feel about it? After you draw up your preliminary budget (for areas except for his), tell him what your goal is for having a budget, show him what you are thinking about and see if he is onboard and see what he thinks his amount should be, get his thoughts. Also keep in mind that budgets will need to be tweaked as you learn and that you can change your budgets each month if need be (it's not set in stone).
My dh doesn't want a "strict" allowance for himself. But I know about what he spends a month, so I just go from there. It's really not a problem for us. I also have a "grace" category (read about this idea on another blog). You set the amount each month and if your dh (or you or unexpected kids activities) happen to go over on something, well, there's your "grace." If the grace didn't get used up, then I decide what to do with it, whether it's held over to the next month or put towards debt or in savings. It's easier to do this than fret over going over, taking out of savings or trying to tweak the budget to make it work.
I need to go back and tweak our budget. I thought it would be good to micromanage what I spend(personal/hobbies), but that's not working out for me. I haven't been real strict and in some areas I need to start being more diligent in staying within my limits I have set. I basically have a budget for myself, kid's commissions and household.