Yea, it’s also not the best example because Mia Farrow was not legally wed though Allen was in a long term relation and they had a child. So, I am not sure if it qualified as a common law marriage before their separation.
In an August 1992 interview with Time Magazine Allen said, “I am not Soon-Yi's father or stepfather”, adding, “I’ve never even lived with Mia. I've never in my entire life slept at Mia's apartment, and I never even used to go over there until my children came along seven years ago. I never had any family dinners over there. I was not a father to her adopted kids in any sense of the word.” Adding that Soon-Yi never treated him as a father figure and that he rarely spoke to her before the affair, Allen seemed to see few issues with their relationship.[196]. https://en.wikipedia.org/wiki/Woody_Allen
However, if your mapping out relationships in software without considering the timeline it looks like a circular relationship. Further, I am sure you can find cases that are actually incestuous.
