Hi Open4,
I wonder if on some level, Donna started to worry that *you* were going to tell your mutual friends that it was *her* fault. Then she figured that the only way to stop that from happening was to preemptively accuse you of the abuse. This wouldn't have had to be a conscious process, as I said ... but she could have been feeling some guilt about her own role in the breakup, and guilt is not a comfortable feeling. Heaping blame on you may have gave her some relief from the guilt. This would be a subconscious emotional process that took some time to evolve. And I could be wrong ...
Sympathetically,
Kevin T.