I can’t really comment on the prenup since we did not get one and probably wouldn’t have even if we were more established when we got married.
We maintain separate checking accounts, a joint savings account, and separate credit cards. This makes sense since we both have our own incomes at this point in time, and we just kept the credit cards separate because there was never a need to add each other to the accounts. Once I transition to a stay at home mom, we may revisit this arrangement and do a joint checking, but will probably keep the cards the same. We are the sole beneficiaries on each others’ retirement accounts.
For expenses, our uneven incomes mean that he covers the majority of our expenses including mortgage and utilities. I cover my own credit card, and my student loan payments. Day to day expenses like groceries, home supplies, and routine medical bills usually end up being split roughly equally based on whoever is available to pay (if we are running errands together, it goes on his card, if not, it goes on mine). This isn't a problem for us because we are both frugal and rarely spend money on anything but necessities.
For me, the concept of combining finances isn’t so much about exactly whose names are on the accounts, but rather how the couple THINKS about their money. Even though we have separate checking and credit cards, we view all income as ours. If I ever needed help paying off a high cc balance, he would happily transfer the money and vice versa. He routinely kicks in extra funds to pay down my student debt faster (he views it as his debt as well). We always discuss purchases together, and ALWAYS ask/confirm with the other if we need to withdraw money from the joint savings. This method has worked really well for us so far, I'd recommend a similar approach.
