My husband and I separated years ago, and during the separation, I lived with another man and we now have a six year old. My husband has since divorced me, and we never claimed my son during the divorce, we need to know how to go about getting his rights voluntarily relinquished, and have my son's biological fathers established. We're all in agreement, need to know how the state of MN handles this.

I'm confused. Who's rights? Who is the father? Why do you need rights relinquished?

As you can read in many other threads here, parental rights have to be voluntarily relinquished (the only exception might be cases of abuse). Relinquishing rights does not relinquish financial responsibility. Generally such a relinquishment is not allowed unless its when a step parent wants to adopt.

The Biological father is determined via a paternity test.

Your best bet to get the right info is to Check with your local Family Court.