Your question is a little hard to follow.
If you posted bail, you were arrested. People who are "just detained" don't have to post bail to be released.
Your wife cannot "file charges." The District Attorney will review the police reports to decide whether to file charges against you.
If the officer didn't read your rights after being arrested, that usually doesn't result in dismissal of the charges. It would only means any statements you made after the point where the officer SHOULD have read your rights can't be used against you.
The officer's comments to your wife may not be true. Police officers are trained interrogators and can lie during an interview to get the information they want. The courts have said it's okay for the police to lie to you in many situations.
If you can afford to hire a lawyer, you should do it BEFORE your arraignment and do what your lawyer tells you to do. If you can't afford a lawyer, ask the judge to appoint the public defender, who is a lawyer paid by the government.
Convictions for domestic violence charges can have severe consequences - the conviction on your record, a one-year long anger management class, probation, fines, restraining orders . . .
Obviously, the details in the police report are going to be important for your attorney to review, but to answer some of your questions:
Miranda: The police are required to read you your rights if you are "in custody" and being interrogated. Them saying at some point that you were only detained isn't the end of the analysis. If you were questioned in a setting where it appeared that you were not free to go, then it could be considered custodial and any statement could be suppressed. You were arrested, that's why you had to post bail. The question will be when you got arrested.
Your wife does not have to "press" charges. That decision is up to the prosecutor.
You should be consulting with an attorney BEFORE your arraignment if at all possible. If you are unable to afford one, then ask for a public defender to be appointed. The concern is that the public defender won't know anything about your case that first appearance and the judge may issue a restraining order against you, effectively kicking you out of your house.