Tsk, tsk, Christina Applegate! US Weekly is reporting that "infidelity" was the reason behind her and husband Johnathon Schaech's recent breakup. Schaech recently filed for divorce siting "irreconcilable differences," but US Weekly quotes a source claiming, "She was cheating on him while she was in New York doing Sweet Charity [on Broadway]. He found out and was furious, and wants out of the marriage." Apparently Applegate was a bit sloppy with her indiscretions. US Weekly also states that someone else saw her making out with a man at a karaoke bar in New York this past November. Way to go all Tori Spelling on us Bundy!! What a bitch!