Kordell Stewart -- Porsha Williams Parties All Night and Neglects My Son

Porsha Williams likes to stay out partying 'til the break o' dawn, and then call police to get her into the house she shares with estranged husband Kordell Stewart -- this according to new documents.

"Real Housewives of Atlanta" star Porsha fired the first shot ... filing a motion that claimed Kordell was locking her out of the house -- and bringing another woman into the home.

But in his response Kordell claims he only locks the house at night for security purposes. He claims the real problem is Porsha frequently leaves home for several days straight ... and sometimes comes back between 2:00 AM and 4:00 AM smelling like alcohol.

As we previously reported ... Kordell filed for divorce last month.

The ex-NFL star also claims Porsha called the police twice to let her into the house ... even though she has a key to enter the property.

As for Porsha's claim of "another woman" in the house -- Kordell says it's the nanny he was forced to hire because Porsha is "neglecting her responsibilities to her stepson."