Kandha, Backup or Real connection?

My colleague who is more friend than coworker, cuz we aren't in same team. Says he got a girl he has known for years 7 8 years. And though not official girlfriend of his, but wishes to marry her. So does she. Though I fail to understand, if that's the case then why am I the person he talks to every night, tells all his future plans, family stuff, curious about my love life etc etc. I feel I'm starting to like him. Not so romantically YET, but you get the point. And I don't know if my constant availability is a ego boost to him? He's just being a good friend and I'm crazy in my head or is there a chance we can evolve into something.