What started as a partnership to have fun, isn’t any more. Michael Staenberg and Stan Kroenke launched THF Realty in 1991 and built it into a $230 million commercial real estate empire. Their much-touted acronym THF stood for “to have fun.” But the fun ended last week in St. Louis County Circuit Court. That’s when Kroenke filed three lawsuits against Staenberg as well as THF Realty and one of the company’s ownership entities. Kroenke’s Dec. 7 legal salvo is complicated, involving multiple…