Can my fiancé adopt my daughter if the dad has not contacted me?

The short answer is "No".

The long answer is that the biological father has rights, even without contact, and you must get his permission and get him to relinquish parental rights EVEN if he's not on the birth certificate, hasn't called, etc.

The other thing is this: Most states require that you be MARRIED for a specific amount of time before a stepparent adoption can go through.

I suggest you get a lawyer.

You will, almost certainly, need an attorney to draw up the adoption papers. So you start this process by consulting with local Family Law attorneys. They will tell you when you can file the adoption petition and what will be required about getting the bio father's rights terminated.