McCormack gave the former Smash director the heave-ho Sunday night, kicking him out of their house after he told her the photos were about to hit the Internet.
Morris had tried to purchase the pics, which show him locking lips with the failed NBC musical series star McPhee in the middle of a parking lot, but the images hit TMZ Tuesday anyway.
"Mary threw Michael out of the house on Sunday night when he told her that TMZ had the photos and that they were about to be released,” an insider dished.
Morris and McCormack have been married for 10 years and have three daughters, 2, 6 and 9, together. McPhee wed producer Nick Cokas in 2008, but they are reportedly separated and have been living apart for six months.