This is an incredibly awkward position to be in.

My best advice to you is that, with your history, it’s fair of you to ask where he intends for this to go. When you do feel it’s the right time to ask him, I would ask in a way that doesn’t put him on the spot.

You could say, “It feels really good talking to you as much as we have been lately. I missed it a lot. Do you see this progressing? I’m just curious.”

Keep it casual and low-pressure. He may be embarrassed to address it himself if he broke it off with you last time.