In a new blog on her Facebook page, KAT VON D says that JESSE JAMES cheated on her with 19 women . . . that she knows of.

She says, "Today I encountered the 19th girl to add to the list of people Jesse cheated on me with during this last year.

"I kept going back and forth in my mind as to what the best way would be for me to release and let go of any residual feelings remaining from that toxic relationship."

Kat says that when she first started dating Jesse she was, quote, "confident and excited at proving the world wrong" about him. But she now admits, quote, "I deserve a big fat 'I told you so,' from everyone."

But she's also sad for Jesse because he seeks, quote, "validation through the attention of women over being a good father, a sincere friend, a better coworker, and a happy individual."

Ultimately though, she THANKS Jesse for the lessons she learned. And her post is even titled "Thank you, Jesse James".

(You can read the whole thing here.)