How can you regain someones love and trust after breaking their heart unintentionally?

When my roommate and I met we really liked each other but he wasn't ready for a relationship. I pursued him for 5 months but kept getting the same result but his actions would say he cared about me and wanted more. I thought it would be better for both of us if I was able to push him away so I tried to start something with someone else even though all I could think about was my roommate. I felt like I wasn't good enough for him and that he would be happier with someone else. After I tried starting something with this other guy, my roommate confessed his love to me. I really wanted to say yes and start a relationship with him but I still thought he deserved better, so I tried making up excuses why we shouldn't be together. It has been eating me up inside and I've been depressed ever since I hurt him and no matter how hard I try I can't get him off my mind. So I decided to tell him how I was really feeling and how it's been tearing me up inside and how much I regret what I did, but he said "to tell you the truth I'm kind of over it". But his actions say that he still loves me and cares about me. I have never been good with showing how much I care about someone. How do I show him that I truly care about him and can't live without him and regain his trust?? I don't know what to do to change his mind! :( Please help!!!