Been living with my gf for 1.5 years or so. Overall, it's been great. We currently keep things seperate. I pay the big chunk of the mortgage, she pays monthly bills and groceries. It works. But, we are looking at doing a combined account. We dump both checks into the main account, pay out the bills, then whatever is left, is split into 2 and deposited into our own accounts. That way, we'd each have our "spending" money for whatever we want without the other being able to say "no". Makes bills easier and still gives you freedom to buy whatever you can budget for.