For us, the biggest difference between managing finances together as opposed to when we were both single has been merging our different styles. We don't have any more to worry about now, in fact it's been easier having a single rent check, utilities, health insurance, etc instead of two of everything, but we've had to work on being consistent. I budget well in advance so my Feb 1 paycheck has already been allocated, whereas Phil budgets more paycheck to paycheck. I've already decided on what date I'll pay the March Comcast bill, but Phil's style is more that he will pay a bill right before it's due with whatever paycheck he received at that time. What's worked best for us is that I budget for everything that is regularly paid, including all of his loans and cell phone, and then the money he makes is used for things that change in price such as gas, groceries, trips, and spending money. Most times he actually has enough for his phone and loans, and then what I've budgeted goes into savings.
It's been a very important process, but it hasn't been as worrisome as people were making it out to be. I'm a control freak and Phil has seen me budget and pay bills well before marriage, so we just agreed that I'd make sure all the important stuff is taken care of. Sometimes it's better to just have one person do the task, even if it doesn't seem fair. There are other things that Phil takes care of that I have no interest in.