Jesse James and Kat Von D
Albert L. Ortega/PictureGroup
11/14/2011 AT 02:00 PM EST
When she started dating Jesse James, Kat Von D was eager to "prove the world wrong" about him.
Now, she says, she deserves "a big fat 'I told you so,' from everyone."
"Today I encountered the 19th girl to add to the list of people Jesse cheated on me with during this last year," the former L.A. Ink
star wrote Sunday in a blog post
on her Facebook page.
"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."
James, 42, had acknowledged to PEOPLE
that he had "poor judgment" in response to allegations
he was unfaithful during his marriage to Sandra Bullock
Von D, 29, says she's "sad" knowing her ex seeks "validation through the attention of women over being a good father, a sincere friend, a better coworker, and a happy individual."
"I tried my best to go through all of this without venting, or complaining, or fueling more tabloid mumbo jumbo," she writes. "[But] this is about me making peace with myself, and forgiving myself for making some bad mistakes."
James and Von D, who had originally been planning a summer wedding, split for good
in September. At the time, Von D told PEOPLE, "I wish Jesse nothing but the best in life and in love."
James has no comment, but a source close to the former West Coast Choppers owner tells PEOPLE Von D's "claim is ridiculous."