I have a friend she is in the process of separating from the “love of her life” she calls him. Says it feels like he is a “part of her” or it feels

Like they are “one whole”, or she “has always known him” or it feels like. I don’t know what to tell her. Any advice for her? She says its “impossible” to separate from him. I have no idea. She has tried this before like 100 times, and always went back to him