My Ex girlfriend from 5 years ago who has been married and has 2 kids is fighting with her husband because he believes the oldest son (5 years old) is not his. There is talk around town that she thinks the oldest is mine. Doing the calculations of our relationship I do not believe he could be mine and she had cheated on me with at least 2 men before we broke up. Since I have never seen this child and nothing was said for the past 5 years, if a paternity test is taked and the child is mine do I have recourse to waive my rights? The child is 5 years old and has been calling her husband "daddy" this whole time. The husband is also who signed the child's birth certificate. I don't want to ruin this child's world and confuse him. Please help!

I don't think you have too much to worry about if his name is on the because and they're married. He has already accepted the responsibility. He would have to request a paternity test to prove he isn't the father. Then they would have to go to court, if he wanted to, to have his responsibilities removed. That isn't easy at all, especially if his name is on the because.
If he is able to do that, then she would have to, somehow, get you to take a paternity test.
You don't have any rights to waive yet.

Even if you give up parental rights it doesn't absolve you of financial responsibility.

At this point, a peternity test would have to done to ascertain whehter you are the father or not. Unless you are forced to do one, don't.

My Ex girlfriend from 5 years ago who has been married and has 2 kids is fighting with her husband because he believes the oldest son (5 years old) is not his. There is talk around town that she thinks the oldest is mine. Doing the calculations of our relationship I do not believe he could be mine and she had cheated on me with at least 2 men before we broke up. Since I have never seen this child and nothing was said for the past 5 years, if a paternity test is taked and the child is mine do I have recourse to waive my rights? The child is 5 years old and has been calling her husband "daddy" this whole time. The husband is also who signed the child's birth certificate. I dont want to ruin this childs world and confuse him. Please help!
I really think you should rethink relinquishing your parential rights. It's a decision you'll have to leave with the rest of your life. What if things don't work out for her and her husband. You still could be obligated by the courts to support the child even if you give up your rights. Also, think about what the child will go threw having his father give him up. Not judging you, just want you to think about it.