A man on Reddit is wondering what he should do after finding out his ex lied about him being the father of their 11-year-old son.

"I’m 30 years old. When I was 18, my girlfriend became pregnant. She told me that she had cheated on me around this same time. I told her it’s okay. We will have the baby, then do a paternity test and go from there," he began.

"She contrived a false paternity test using the real father’s DNA and put my information on the test. I fathered that child for 11 years before catching her cheating," the man continued.

When he confronted her about cheating, she denied it, so he decided to do a secret paternity test since his son doesn't look like him.

READ MORE: Dad Starting to ‘Resent’ 13-Year-Old Son From Wife’s Affair

"This is when I found out that the boy was not mine. This has obviously stolen so many years of my life and created a huge issue for the boy as well. She used a contrived test to convince me I was the father and showed this test to tons of people," he explained.

The man noted he has the "proof of both tests," but has been unable to get the authorities to listen to him.

"I spoke to a lawyer and I know [with] 100 percent certainty that she has committed a felony against me. She is 100 percent guilty and I have all the evidence that would be needed," he wrote.

The man added he has "completely lost faith in the legal system because of this."

READ MORE: Paternity Test Goes Wrong When Both Parents Find Out Child Isn’t Theirs

In the comments, Reddit users urged him to think about the child and the fact that he is the only dad the boy has known.

"Based on the information you provided, it sounds like you did some type of home test as opposed to going to an official lab where they check the ID of the person giving the sample to ensure this doesn’t happen? If that’s the case then you do have an uphill battle to climb. You should consult with a family law attorney but you usually cannot challenge paternity after 11 years. Regardless of DNA you are considered the father of that child," one user wrote.

"Step up, you’ve been this kid's dad for the last 11 years. Some random (or not so random) test doesn’t alter this. The legal system agrees with this assessment as they should. For all intents and purposes you are this child’s father. Act like it. Yes your ex lied, yes she cheated, yes actions taken 11 years ago would have altered this situation. But none of these facts alter your responsibility to the child now," another chimed in.

"You could try to talk to a detective and see if you can file a case against her for deception and changing a legal document or medical document ... That might be the route you can go," someone else commented.

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