I am having to deal with this right now. My ex is 50, his gf is 25, I am 45. My ex an I have children 10 yrs younger, same age, 3 yrs, and 4 yrs younger than the gf. I am having to deal with the gf living in our house, and she is a major trigger for me. I have borderline personality disorder. None of the 6 daughters approve and no longer talk to him and he doesn't care. It is supposed to be family first, and he doesn't care. It really pisses me off. I can't stand to see, hear, and be around her.