Don't share your bank account and definitely don't mix business / pleasure.
Having gone through the resulting break up 4+ years ago now, it's not fun and likely you could be wiped out (I was literally wiped out, 100k+ in debt, which I've since dealt with and a credit score that will likely never recover at about 430).
If I look back, the key moment where we should have done the right thing and ended the relationship was 9 years earlier when she cried and said: "my friends all tell me if we don't have joint bank accounts it means our relationship has no trust and we'll have money issues down the road, if you loved me you would put my name on your bank accounts/credit cards"...
My correct response should have been, "if you loved me you wouldn't ask me to do dumb shit that means nothing" .. or better "fuck off and don't let the door hit you on the ass on the way out".
The wisest thing I can tell you, if your significant other makes a big thing of having a joint bank account or more specifically her name on your assets, find a way over time to get out of the relationship, you'll end up fucked later otherwise.
I've since moved on and my new girlfriend (now wife) and I have completely separate financial identities, I can't think of any credit or bank account where both our names are present. We are very very happy at least in part as a result. In fact, she pays our general bills and monthly I simply auto send her a cheque. And she's younger, smokin' hot and loves sex.
Basically, fuck that, don't do it.
Additionally, in the US, it's REALLY hard to get an account closed or someones name removed from an account once they are added. You'll basically have to close it. The touch of irony in all this, when we first went to the bank to add her name to my primary account, the lady at the bank said "don't do it, you'll regret it!" .. My now ex-girlfriend was fuming/pissed off, face bright red pissed off. That statement stuck with me and if I ever see her, I'll thank her and tell her how much of a dumb fuck I was.