I need help....

My boyfriend has some issues and I can no longer think of ways to try and help him. Ever since he can remember he's kept his big problems to himself and didn't tell anyone. To me, I don't think that's healthy. He has hurt himself in the past by cutting, and recently he's been doing it. I know he has because he tells me when I see he has a bandage and I ask what happened. He says its not a big deal and I shouldn't try and help him anymore. I've told him that I love him and care about him and want to help but all I get back is "I know you love me. But don't try and help. You can't." If anyone can help me.. I'd really appreciate it. Thanks.