Crush on a married guy. I am married too but he just doesnt know.?

We commuted together. He caught my attention then he started convo. Without him knowing in the first place, I was head over heels when he approached me. After a while, I invited him to lunch on my birthday, he treated. He hardly mentioned anything about his wife or his little boy..I only noticed from his wedding band that he's married. I am sure he can tell that he's special to me through my cards and emails.. I call him once in a while and email him every now and then just to keep in touch. He moved and we are not travelling together anymore for almost a year now. I still have this strong feeling of liking him. My face brightens if I see him ... He never initiates any calls or emails but if I call or write, he reponded warmly and interestingly. What's on his mind? Why didnt he just give me cold shoulder or ignore my calls or emails so I can get the message "it's time to stop !" HELP !!