The concept of the show is simple. If someone feels that their partner is not being faithful, they seek out the help of the Cheaters team. The show then sends out its private investigators to essentially spy on the partner in question. Over the course of a few days, the PIs collect evidence that either proves or disproves their suspicions.
Due to the sensitive nature of these confrontations between the host, the cheater, and the client, things tend to get quite fiery on the show. In 2003, Joey was the victim of a stabbing during one of these confrontations. This incident raised questions over the show’s validity, leading it to be considered “fake” by critics.
However, it gave Joey notoriety. Cheap stunt or not, it was one of the few things that contributed to him becoming a fan-favorite of the show.
Source : https://www.distractify.com/p/what-happened-to-joey-greco