My daughter age 20 has been with her boyfriend for 3 years. He has repeatedly cheated on her the the whole time and she keeps forgiving him. He has just done it again, he tricked an 18 year old into sleeping with him by saying he is single and looking for a seriouse relationship. He makes me feel sick and I can't stand to have him in the house anymore. She won't listen to anyone's advice. Any advice please, it's breaking my heart.