Belafonte 'Was Convinced' & Falsely Accused Her Of Having An Affair With Simon Cowell

More dark secrets are beginning to emerge about what ultimately led to Stephen Belafonte and Mel B's marriage collapse — and Simon Cowell is being falsely accused for it!

According to The Sun on Sunday, Belafonte believed Mel B — real name Melanie Brown — and her X Factor co-judge Cowell were having a steamy affair behind the scenes of the show.

"Stephen's jealousy at that point was causing massive problems in the marriage — and he was convinced something was going on between her and Simon," a source told The Sun. "He did not like the fact Mel obviously looked up to him and spoke about him a lot."

During the show's finale in 2014, Brown missed the first night of the two-part showdown due to being hospitalized for overdosing on pills. However, after filing for divorce last month, speculation grew that the star took a beating from her convicted felon hubby over their blowout about Cowell.

The former Spice Girls star managed to show up for night two of the show, and was allegedly able to cover up the bruises on her face and arms. "He thought she was up to all sorts at the time — but accusing her of sleeping with Simon was a real low point," the insider went on.

"He just couldn't control his jealousy and anger when she was appearing on such a high-profile show with successful people that he didn't know," the source said. "It caused huge arguments that led to a loss of trust that never really healed," added the insider. "It is definitely one of the things that led to the eventual breakdown of their relationship."

Still, when the X Factor cast and crew discovered Belafonte's raging temper, and he was quickly banned from visiting the studio. "There is no truth in the accusations that anything happened between mel and Simon," an X-Factor source told The Sun. "They don't even have a flirty relationship. Simon likes her, and think she is professional, so looks out for her as a friend."

As RadarOnline.com previously reported, Brown filed for divorce on March 20, then filed a restraining order against him after accusing him of emotional and physical abuse during their 10-year marriage. The 41-year-old singer also recently slapped a restraining order on her former nanny, who she alleges had an affair with Brown during their marriage.

Despite Brown asking for custody of their 5-year-old daughter, Madison, Belafonte recently fired back with his own custody demands by saying, "They are the only things that matter to me." Belafonte is also step-father to Brown's two other daughters from her previous marriages — Phoenix, 18, and Angel, 10.