Recently I notice a guy who I have been in a rapport with suddenly become distant on me. He is a nice person, we talked a lot when we met and we also trusted each other at some point. He has a girlfriend and on the other hand, I have no romantic interest in him. I appreciate him as a decent guy, so when we have contacts, I always respond as soon as I could, when he asked me for help, I tried my best to help. I also sent him birthday card and sent him sweet words once in a while.