Music mogul Jason Flom and his wife, former Atlantic Records A&R exec Wendy Berry Flom, are heading to court today in their increasingly dirty divorce trial.

Flom is CEO of Lava Records — which has played home to Matchbox 20, Kid Rock, Sugar Ray and, currently Jessie J — and he has previously headed labels Atlantic, Virgin and Capitol. He has worked with artists including Lenny Kravitz, Coldplay, the Rolling Stones and he personally signed Katy Perry. He’s reportedly worth up to $100 million.

Jason and Wendy’s bitter divorce has been dragging on since 2010, when the 20-year marriage abruptly ended. A source close to Wendy told us: “Wendy insists she was hugely influential in helping Jason’s career and wants half of everything. She claims she helped him establish Lava Records in 2009. But Jason does not want to cut the check and pay her the settlement she is demanding. He is saying she had nothing to do with his company. Is she suddenly supposed to enter the workforce again at 50-something?”

But another source tells us, “Wendy is fighting hard to get what she wants and is making a lot of wild claims about Jason. It will all come to a head this week in court.”

His wife claims that since the pair split, Flom briefly dated Tiger Woods’ one-time mistress Rachel Uchitel and he has been “partying nonstop.”

But Flom said of any such wild behavior, “That is absolutely and categorically not true. I do not touch any drugs of any kind, ever. I have [been an advocate] to decriminalize drugs, but I don’t do any drug whatsoever. I don’t smoke pot. I don’t even take NyQuil.”

Flom referred any comment on the divorce trial to his lawyer, John Kornfeld of Aronson, Mayefsky & Sloan, who did not return calls. Wendy has retained power attorney William Beslow. He also did not respond to a request for comment.

According to a 2010 report, Flom said of the split, “I am focused on resolving this situation amicably.” But we’re told things are far amicable, and Wendy could take the stand Monday in the trial — and she’s ready for battle.