Why my ex would do this?

My ex left me and when she left said there was no one else. I do belief that when we seprated there was no one. However during the sepration she did meet someone. We end up divorced. She was living with her cousin and then she ends up renting a duplex at the end of my road that her uncle owns. Her parents live next door to me. Her parents are not a problem for me I mean her dad cried a little when she was getting her stuff out of our house. The first weekend she moves down the road from me she has her new man stay with her. He is always there and it seems they never go to his place if he even has one. Why would she move at my doorstep knowing how hurt I was and even seeing her dad hurt. She brings this guy to her parents house on Holidays knowing her dad does not approve of it. What makes a woman not care this bad. I did not do anything really bad to her like beat her or stay out drinking. I guess I am saying I would not shove my new life in her face if the shoe was on her foot