What does it mean when a man says he is "in like" with a lady?

This is my ex-fiance and we have been friends since breaking up a few years ago. He had an happy tone when he told me the news, and just responded what do you want me to say. He did not know what he wanted me to say, so it was left at that. I am currently dating a guy but that is head over heals and wants to eventually marry but my heart is with my ex deep down. He told me this for when he was interested prior in another relationship, I couldn’t handle it and told him so, guess he broke that off for he did not want me to cut off our friendship. What to do?