Guys: Do you ever feel bad for hurting someone real bad?

I know I do. There is a guy in my past that I hurt ( not intentionally) but we were best friends and he liked me more than that..when he professed his love for me and cryed his eyes out, it made me feel bad. I had to cut him out of my life and since then I have felt bad. I tryed keeping in touch but he still has feelings for me so I can't. This has been 14 years ago. That was bad enough so I can't imagine intentionally using someone and hurting them. I wouldn't be able to live with myself. So I am curious, how do you do it?