Weber, who won the U.S. Open in 2005, has been in a relationship with the Canadian-born woman since 2015.
According to the Daily Mail, the two have been together for almost four years.
Weber has said he has no interest in a divorce and that he will keep his relationship with Berthoud open, the Mail said.
Webers publicist, Jodie Meehan, told The Associated Press that the tennis star has not yet spoken with the tabloids and is focused on his upcoming tournament.
Meehans statement said that Weber and Berthoutts “love each other and have been since last year when he returned to Canada and became a husband to a beautiful woman named Barbara.”
Weber was previously married to Canadian tennis star Caroline Wozniacki.
Berthouts publicist did not respond to requests for comment.
The Mail said the relationship has been going on for about five years and that Webers family is worried about the health of their two children, a girl and boy.