Absolutely, it's okay -- at least in my own relationships. In both of my marriages, I've ended up with men who seem to think that just because money is there, it can be spent. In my first marriage I was still working for that twice-a-month paycheck for most of it. I had stock options, so I put in the maximum contribution ($75 per paycheck) which the company matched 15%. I didn't tell him that I did that, and he never looked at my pay stubs. He looked at the amount on the check, and assumed everything else had been taken out in taxes. We had more than enough for all of our needs, and had he ever specifically asked then I would have told him.
In my current marriage, I started by putting money away in secret savings. When we ran into financial troubles, I had to drain the account to meet those needs. However, now that he knows it's there, I've just told him that I have money but it's not for spending, and I keep the attached debit card in an undisclosed location. He understands that I work for myself, so my pay isn't extremely stable -- I might get a $2,000 paycheck one time, and then not get anything for several weeks or even longer after. The only way to ensure that bills are paid is to keep an emergency savings account. He still occasionally tries to get me to spend the money, but if it's not something we NEED then I tell him flat-out that he can't have it.