"I think Madonna is more significant in terms of custody and visitation," he said. "She's going to try to show that A) kabalah's a cult, which can effect visitation, and B) Alex is giving money to kabala instead of the kids."
Alex and Madonna reportedly started working out together last November, and from then on friends say he became infatuated with her.
"This year all of a sudden he sat and listened to a lot of Madonna's music and videos and DVDs and stuff like that," Romero said. "That was my red flag that there was something drawing him to that.
Us Weekly reported last week that Alex had paid late-night visits to Madonna's New York apartment, though both of them denied the report.
Madonna, who is married to film director Guy Ritchie, told People magazine Sunday that she has not had any romantic involvement with Alex, and that there were no problems with her marriage.
"My husband and I are not planning on getting a divorce," she said. "I brought my kids to a Yankee game. I am not romantically involved in any way with Alex Rodriguez. I have nothing to do with the state of his marriage or what spiritual path he may choose to study."
Madonna isn't shy about her faith. In a 2004 interview with ABC News' "20/20," she credited kabala with making her a better person.
"In kabala you learn that you never know, you never know about people," she said in the interview.
Demi Moore and Ashton Kutcher also practice kabala and several other celebrities have been linked to the faith.
Lilly said that Cynthia has hired him to head a team of lawyers in the divorce case, KTRK reported.
Lilly, who has represented numerous celebrities in the past, told the TV station he was hired this past week, along with Maurice Kutner of Miami.
ABC News spoke with Kutner, but he declined to comment until after the divorce papers are filed Monday.
Lilly told KTRK that the suit cites a "long period of infidelity on the part of Mr. Rodriguez, an all-star baseball player for the New York Yankees," and also claims "emotional abandonment."
Madonna is not named in the suit, Lilly told KTRK, but he said that A-Rod's "affair with Madonna was the final straw for Mrs. Rodriguez."
KTRK reported that Cynthia was in Miami and not available for comment on the advice of her attorneys.
Attempts by ABC News to reach Alex and his attorney were unsuccessful.
The divorce filing comes after months of speculation that the Rodriguez's marriage was on the rocks. The rumors have made Alex as much a staple of the New York tabloids' gossip pages as he is of the sports pages.
When he was photographed last year with a former Las Vegas stripper, the New York Post labeled him "Stray-Rod." Even the Yankees' lackluster season has been blamed on the distraction caused by the rumors.
Apparently, even the birth, in April, of the couple's second daughter was not enough to save the marriage.
Alex and Cynthia were married in 2002 and have two children, Natasha Alexander and Ella Alexander.