My ex is weird

So my ex of 4 years and i have been broken up for a year! He found someone new fairly fast (like 2 months of us calling it quits) & their relationship was moving fast! I feel as though he should’ve took his time instead of jumping into something else as fast as he did. It was something new and he couldn’t wait to have it. He’s recently refollowed me on Instagram even though my page is public. I know I shouldn’t be concerned about what he’s doing but apart of me feels like he wants to come back without saying the words.