Why can't I love anyone else?

When I was young use to be incredibly emotionally dependent on some body else to feel happy, I was always in and out of relationships and they all ended in heartache, I felt puppy love but the novelty always rubbed off until I met someone at the age of 17, he was 23 and I was absolutely head over heels inlove, it lasted about a year and he was my best friend, we never had a fight or disagreement, he seemingly loved everything about me and I loved everything about him, he had a baby before we were together and our relationship ended when the mother of his child moved into state and he had to move to stay connected to his baby, I told him I completely understood and even though it broke my heart it meant more to me for him to be happy, I was trying to come to terms with the situation and move on when a short period after (I don't remember how long but it was a week or two) I found out he was in a relationship with a new girl which caused a falling out in our friendship so we stopped communicating. I was in two relationships after that but I never felt anything more for them then friendship, at the beginning I told them both I didn't want to be in a relationship with them but I was pressured into both relationships I guess due to my low self esteem I didn't know how to say just say no because I didn't want to hurt their feelings, after my last relationship ended I decided not to settle for anyone or commit until I learned how to be emotionally independent, it's now been 5 years since my last relationship and although I've had absolutely gorgeous guys try to peruse me in this time and I am so happy and confident with myself I just feel numb when it comes to boys and it makes me feel really sad, I'm now 25 and once in a blue moon he still pops into my head and I'll look at his facebook page, shortly after my last relationship I sent him a message asking to be friends and it went well for a week until he asked me to come over to his house and specified that I couldn't stay the night because he had to be up early for work, I took this as a "booty call with no strings" proposition and it made me realise if I saw him the feelings would still be there and I would get hurt and I'm not stupid enough to do that to myself so I decided to stop talking to him, I've really tried to move on but 8 years later and I still feel that pull toward him, will I ever be able to move on and be normal? It feels like I'll never care about anyone again, I really miss having that special thing with someone, I'm so sick of it and at this point I want help :(