I am the wife, but I don't have POA. Now what?

If he is still competent. go online and use Legal Zoom or another service, fill out a POA and have him sign it. Do not wait, you still have a window of opportunity.

Very sorry.  If you do not have a durable power of attorney, if he is still competent,  you can get one now.   You can generally download one online, make certain durable, and for your state.  You will need to get it notarized, and if your DH does not appear competent to the notary, he should not sign.  If DH has already been judged incompetent by a doctor, he should not be signing a POA, but in the early stages of dementia, he is likely competent, at least on some days/times.   If he is not competent, you will need to go to court and have yourself named a guardian.   If this is a second marriage, there is always a risk his kids will want to be guardians.

Why can't you get POA now? Has your husband been declared incompetent?

Is your husband in need of Medicaid funding? Have you consulted a certified eldercare attorney ?