Agree, don't listen to anyone who contacts you with email or saying they will cast for you.
This reminds me of my friends. I have a friend who was dating this guy on and off for many years. They met online but his manipulation and hold was so great she left school for a semester because he didn't trust her going to school so she spent 6 months locked in her room constantly on her webcam. They would break up and he would try killing himself [once he sent her a live video] and they would get back together eventually to follow the same pattern. About two years ago my other friend [who had been in love with her for years] finally asked her out and they started dating. I'm sorry to say it didn't have a happy ending for him. My female friend was contacted by the abusive ex who said he changed [his old doctor had been giving him the wrong medication for a mental disorder he was born with, his new medication fixed everything and he wanted her back] after a few months of talking they got back together, they're now married with a kid [and yes he is completely different, but I do keep an eye out for her] our friend who loved her for all those years was destroyed by the heartbreak and is just coming around now.
The point is a. Love isn't logical, b. If the person doesn't know themself they will repeat behaviour, c. Don't go in with your eyes shut. Just because you date doesn't mean he will love you forever.
If you really love him, instead of casting over him to make him yours, talk with him, and try to help him understand himself, build himself up, and move on. Don't manipulate him [which can ne hard if you want him badly] be there, and be prepared that he might return to her. You need to also ask yourself if its all worth it. You should look inside yourself as well and figure out what you want and why.
Magickally, I would do cleansings, protection, maybe healing, but to help him with his demons, not to make him do what you want.