What does this mean?

Me and this dude had a thing and he ended it. We stayed friends as we were good friends before. After he was leaving flirty comments on another girls Instagram. They unfollowed each other like a month ago. And since he’s been interacting with me a lot. He lives in another state so it’s been through snap or Instagram. A week ago we drunk snapped each other and in one of them he sent hearts. His snaps cont to the next day. 4 days ago he was sending me stuff all day long too. Literally the day after he followed that girl again and she followed him back. Since he’s been interacting but not as much. He’s been snapping me and replying to stories I post. The only thing is that i snapped him like hours ago and he hasn’t opened it. He’s in the military so I think he’s on one of his trips or just got done based off the snaps he sent. But I guess I’m just worried he’s talking to that girl again. I can’t see her Instagram cuz it’s private, but he wouldn’t interact with me this much before. He’s the type of person who will be friends with exes unless they really f’d him over. I’m just thinking he’s not replying bc he’s busy ? I wish I could ask him but I don’t feel like it’s my place yet. Idk what to think???