My sister got cheated on by her bf of three years. I told them long distance wouldn’t work and a month in this idiot runs to the first sign of attention from an absolute 4. He doesn’t know that she knows yet and my sister is feeling pretty down. (F24)

I recommended that she just blocks him and goes no contact but she basically responded “it’s logical what you are saying but I won’t do it.”

I want to help her and guide her through this but not sure how to, I don’t support her going off on her ex bf but I also want to make her happy and do whatever because I know it will be a tough period in her life. Anyone ever experience this? Any advice?