advice about a friend

so i have a friend who has gotten back with a guy for the third time. she changes so much when he's in her life. not to mention, he called her a bitch during the second break up. he lures her in by buying her food and apologizing but then is disrespectful again. she has said before that he reminds her of her father, who has NUMEROUS baby mamas, and has been disrespectful to women in his past.

i just don't know what to do anymore. she becomes his wife basically and jumps when he says jump. i HATE being around her when he's in her life because she also becomes not herself. she knows this and is still willing to be with him. she has other options... she's not trapped... she WILLINGLY wants to be with him. is it bad i'm distancing myself from her bc i don't want to deal with that? i've slightly lost respect for her bc he's been disrespectful towards me, and she doesn't correct him or say stop. (he's not abusive, just rude). i've tried talking to her, but she gets defensive and dismissive about it...