According to Brian Niemietz of the New York Daily News, Sanchez and Reyes had a daughter together, and they acted as Reyes' road family: "We'd go to restaurants, go to games, go shopping, that was the life I was living. It was a double life, but I wanted him to be a father of our child."
Sanchez is currently suing Reyes for a child support increase from $11,000 to $41,000 per month for their seven-year-old daughter.
Reyes married Katherine Ramirez in 2008, but Sanchez said she and Reyes were romantically linked before that marriage.
Per Niemietz, Reyes hasn't seen his daughter since 2015, and she believes the situation is taking a toll on him from an on-field perspective:
I think so. When you're a father you're going to have something in the back of your mind bugging you. You have to be broken inside to shun your own flesh and blood. If he does the right thing ... we all make mistakes, I apologize to his wife, I as a woman want to apologize to another woman for what I did. But he hurt both of us.
As New York's starting third baseman, Reyes is hitting just .079 with no RBI so far this season.
He rejoined the Mets last season after getting released by the Colorado Rockies.
Reyes was suspended for the first 51 games of the 2016 campaign due to a domestic-violence incident involving Ramirez. Prosecutors dismissed the charges after Ramirez didn't cooperate with the investigation.