I have been married for 3 years and have a 1 1/2 yr old son with my wife and recently found out she has been cheating on me on multiple occasions from when I was home but in the field to during my whole deployment and plus I recently found out the child wasn't my biological child.
I'm active duty army and stationed in Washington but got married in MA and that's where he was conceived too... At conception I had no doubt he was mine and signed the birth certificate.
I also did a DNA test and the results came back 0% paternity.
I just filed for divorce but I'm wondering if I'm still going to have to pay CS.
She admitted she knows who the biological father.
She knew it from the beginning and just lied about everything.
Please help me out here!

In all US states, when a child is born to a married couple, the husband is presumed the father. Since you also signed the birth certificate you are the legal father and, unless you can get that changed, you will be required to pay support.

I'm not clear whether WA or MA laws apply here, but some states have a limited window of when paternity can be challenged. So I would strongly suggest you get a Family Law attorney to assist you with the divorce and advise how to challenge paternity.

At this poin t unless you can change paternity, you will be the legal father and have custody rights, visitation rights and will also have to pay child support if you do not get custody of child.

There is limited to time to challenge paternity, so you need an attorney now.

At this poin t unless you can change paternity, you will be the legal father and have custody rights, visitation rights and will also have to pay child support if you do not get custody of child.

There is limited to time to challege paternity, so you need an attorney now.

I am currently deployed and was also deployed during the window in which I could challenge the paternity since I deployed right after his birth, can this be excused in any way?

I am currently deployed and was also deployed during the window in which I could challenge the paternity since I deployed right after his birth, can this be excused in any way?

Depends on the courts. Again, I strongly suggest consulting with an attorney who will know your local laws and courts.

The most important question is which state has jurisdiction over the case.