Is he interested in me again?

I was seeing this guy I work with (but not in the same department) for a year and a half. We were just talking nothing serious. At the time, he was going through a divorce. He wrote me everyday and seemed very interested. He told me from the beginning that he wasn't ready for a relationship, but we still talked. No , just kissing.He told me that he wished he would have met me at another time in his life, because he could totally see himself with someone like me. He also said that he liked me a lot, but he just wasn't ready to give me a relationship like I wanted. He broke all communication with me because I got mad at him for talking (friendly) to my friend at a bar, and totally ignoring me. He and I didn't talk at all and he even told me to erase his number from my phone. I was completely hurt, as I went from talking to him everyday, to nothing at all.There was so much tension and hate whenever we saw each other.He now has a girlfriend and I must say that I still like him a lot. I still get erflies when I see him at work. Recently he has been very nice to me, and has even started conversations with me. I catch him staring at me a lot, and has even asked to help me with some boxes I was carrying in. He has also waited for me and holds the door for me. When it was his Birthday, I told him happy bday, and he responded very well. Jokingly he said that he was trailing closely behind me in age. He's also been very attentive as to when I get to work and asks me about my schedule. He jokingly tells me I'm late when I do get to work a bit late. He sometimes distances himself from me, but sometimes is very friendly. He knows I want something serious.Why does he stare at me with longing eyes? Please help! I really like him.