We combine our money. Even before we got married, I worked 3 jobs while in college to pay off his huge credit card debt so we could start our marriage debt-free (well, aside from school loans). I have a hard time imagining how separate finances would work. But I guess if you prefer to do it that way, then you should each have bills you are responsible for? And I guess as long as each of you paid your bills, you could manage the rest of your individual money however you want? How is this going to work when you do eventually have children? Do you have a lot of joint expenses? Do you each pay half, or is it proportionate (by income or usage)?
I would budget your income based on 28 hours a week, since it looks like that's the minimum you'd have, and then have a system for spill-over... so if you worked a 40 hour week, the extra 12 hours would go into savings or toward some unnecessary personal expense.
Regardless of whether you combine or separate your money, it might help if you both agree on the amount of money that you can spend on yourself each month. He might see you getting your nails done or paying for a class or a magazine subscription and figure he is spending a similar amount of money on the computers, it's just all at once (big expense vs. little expenses that add up all month). If you each have discretional spending $ then you can feel free to do whatever it is you want to do with it.
Here's how finances work in our house. DH & I both put whatever we make straight into our checking account. Sometimes he has made more money, sometimes I have, sometimes we have gotten benefits through his job, right now they're through mine. All the money goes together -- ALL of it -- and I pay the bills from that account and transfer extra to savings. We don't really spend much money each month, if we did I'd give us each a stack of cash eash month, but since we don't, if DH or I needs something (new shirts or gadget or whatever), I get it for him on freecycle or shop the sales. Usually we shop together or at least agree on products, price ranges, etc. ahead of time, especially if it's a big purchase. DH came into our marriage having no idea about finances, credit, budgeting, bargaining, etc. but because we shop together he has come a long way (and at the same time, I've learned to let it go when he occasionally spends $10 on something I could have gotten for $3). Since we have a lot of savings, we can decide together that we need something (a GPS, a vacation, etc.) and know we have the money to do it.
Sorry this is so long-winded, just trying to paint a picture for you!
I also think you need to discuss holding off for a baby 'til you're financially ready. You'll never feel truly ready, so you may want to decide on concrete goals ($X amount of savings, $Y annual income, etc.) that you feel would allow you to provide for a kid. For us, that was just waiting 'til DH was done with school & in a full-time job, but if you both already have jobs, you could start saving up any extra so you can reach your goals...
we handled money very differently- I was a free spender and DH was tight-pursed. We divided bills so that he was sure we'd have them covered and I could do what I wished after paying my share.
