What would you do.....I need help!?

I am torn apart by this horse I have, I love him and I don't. He is constantly getting out of his pasture, he has done nothing but misbehave on the lunge line, and I have a hard time riding him when my trainer is not with me. Part of me wants to just give up and say that enough is enough, another part of me wants to keep trying, we're bound to solve our problems soon. What would all you horse people out there do? Any solutions to our problems? I am going to try joining up with him this afternoon, do you think that will help?