I'm about to break up with him. HELP!!!

I don't know why I feel this way. 
I just feel like I just need to break up with him. I'm making myself feel heartless right now, to prepare myself to talk to him and break it off. We're in a LDR, I just don't think this will work out anymore. 
I feel like he's only with me because of lust and not love. I noticed this, the first time he came to see me, he acted different towards me while in public then when we were together privately. I feel like I'm just wasting his time.
I have work and studies and he's a business man. He's at a point in his life where he'll be getting ready to settle down. I'm still 18 and focused on my future career. 
Am I being selfish for breaking it up because I just don't feel this will work out??
Mind you, he hasn't been contacting me back that much after we last met up. I initiate all that now. 
Why do I feel this way?? HELP ME SOMEONE PLEASE!!