Fortheloveofjames - especially as you aren't married you need to consider, even ask, what your bank is likely to do if they're told one of you is no longer compos mentis or dies. Lots of banks in these situations freeze the account.
Then there's if you split - and before you say "he'd never do that" that's what I thought too - ex emptied bank account leaving me (and 2 yr old dd) penniless!
"We are a family so all money is family money, neither takes the piss and big spends are agreed." Most are replying like this poster, basing it on when things are going well. It's when things go wrong you can encounter problems. As I said, not just relationship breakdown (and given the rates of divorce/separation I think it naive at best not to consider that a possibility and behave accordingly). But also critical illness - especially conditions that can lead to unguarded spending - and bereavement (especially of you're not married).
"Sharing a bank account dates back to when wives were just chattel and to be "kept" by the man. We're in the 21st century now and every woman deserves her own money under her own control. And, increasingly with the quality of men out there, we need it incase we have to make a quick exit!" Totally agree with this.
I'm especially concerned for those of you who are sahm or pt in order to cover childcare. Do you even know what financial position you would be in if you were to split? Bear in mind it can take years for divorce financial settlements to be sorted AND a lot of men don't pay maintenance until pursued by cms (and even then it's not guaranteed and the rates are woefully low).
If he dies are you sure you get the house? Any other inheritance? I've a relative who was unmarried but effectively widowed with 2 very young children. Lost everything including home as she wasn't next of kin legally. "In laws" who she thought she got on OK with took the lot! The children were so distressed at the sudden loss of the father she had to give up work, at least until they were feeling more secure she was unlikely to disappear too (and that took a few years & therapy).
If he becomes critically ill and his decision making questionable/he's then a vulnerable adult are you still going to be able to access accounts that could arguably be "his money" when anyone else only has your word that "this is what he'd want me to do"?
Having your own account "just in case" is honestly advisable. I wish someone had said this to me. I had a frantic few weeks of no money, parents having to transfer money to an acquaintances account to give me until I had my own open and working, plus several weeks waiting for wage/benefits to go in and I was VERY lucky to get a job quickly I doubt that is possible in the current market - this was 16 years ago.