On the flip side there are plenty of stores of kids coming up in a good household with good money who gravitated towards that life as well. There are just a lot of people out there who are attracted to danger and love the rush. Now I wouldn't categorize that as the majority of women in abusive relationships but there are a large amount who love the danger of the situation.
I learned through one of my former close female friends. She was in an abusive relationship for years where we told her to get away from dude. She finally gets away and dates a few nice guys and was bored and went back to dude. He swears he had changed. He of course ends up beating her ass again. I asked for his info because I was about to go fight him myself since I don't play that abuse shyt. She refused to give it up since she loved him and didn't want to see him get hurt.
You’re calling it danger and a rush but it could just be a simple love of controlling personalities.
A wealthy person in a loving family could be a dominant personality. The father makes all the decisions, runs the finances, picks the vacations. Etc.
So the person equates a dominant personality with love.
I can’t diagnose your friend but I’d bet it was more complicated than just running back to him.
I have a Latina friend from a loving family who ended up with an emotional abusive dude(29 to her 19). She only broke free when she ended up making more money and basically shattered the man of the household image she grew up idolizing and got tired of his BS.