He brought up his ex and it’s not the first time

We met back In high school. He asked me out and I said no. Then I introduced him to my friend group. He dated my friend. They broke up but me and her remained friends. We then stopped being friends because she would hang out with my ex behind my back and lie about it. A year later I started dating him. It’s 4 years later now and he has brought her up these past two months more than once. We decided to get a dog and he said he didn’t want a dog that was the same color as hers and that barked so much like hers.. ok? Then today while we’re watching tv he goes, “this is like that show that __ used to watch”.. I said “because I want to talk about her, right?”. He apologized and said that he thought it’d be fine to mention her. Why after 4 years are you speaking to me about her? I don’t want to converse with you about any of your ex’s. I’m just annoyed. Then he had the nerve to say “don’t you bring her up too?” knowing damn well that I don’t, that really upset me.

He said he seen her one time about two years ago and when he seen her, he left the location. I told him that he was making me uncomfortable when he brings her up and he apologized and said he’d stop.