Wasting my time?

I feel like he still misses his ex. What are some red flags?

Edit: I don’t remember every single time, but last week we went to get ice cream and he was like “I dont even want to talk about this area” and told me we were in her neighborhood. But when we were 5 minutes from where me and my ex used to spend time I didn’t mention it nor was I uncomfortable being there. We went to the mall and the movies, both of which I know my ex goes to. I said nothing. It’s just starting to rub me the wrong way, especially because yesterday he was texting somebody on twitter and I’m 80% sure it was her.

The other time was her birthday. My ex’s birthday is February 15th. I said nothing to him. On his ex’s birthday in March he told his sister that it was his ex’s birthday while we were on the phone and went out of his way to say that he wasn’t telling her happy birthday. Maybe I’m nitpicking? But why bring her up in the first place?

I’m really bad at asking questions in the moment. I don’t like having to “who’s that, what’s this, why are you doing that” so I don’t really know how to go about it. The next time he brings her up I’ll say something. But early in our relationship it was a problem bc they still talked, he still follows her on socials, and when I told him I was going to leave bc of it he said he would stop. So I’m really irritated and if I ask to see it he’s gonna give me some bullshit reason why I can’t