Family obsessed with ex wife

Boyfriend was married 22 years ago and got divorced in 18 years ago in 2004. We made 1 year together last month.

My issue is that it feels like every chance he gets he talks about his ex wife. Don’t even get me started on his mother. I see her maybe once every few months and she talks non-stop about the ex-wife. I told my boyfriend that the next time his mom comes over he needs to be up front and tell her to stop talking about her.

It will be little things like one time we went to a restaurant that had beets in the potato salad and he says “oh I remember my ex-wife father used to put beets in his potato salad”

Another time we were watching a movie about a wife that cheated and the husband wanted to get revenge, so out of nowhere he says “you know you can sue someone for ruining your marriage” I replied, is that what you did…he responded with “I almost did”

Another time, he told me that I remind him of his ex wife, because I went to Sephora and went over my spending budget. I responded with excuse me, he said all women are the same just want to spend money on make up.

His mom also called him the other day to tell him that his ex wife was getting emergency surgery in her ear. I told him why is your mom calling you about this. She has a new husband in her life.

Another time, we were watching this show and he mentions that the actress looks exactly like his ex-wife.

There have been other instances but too many to list.
My main issue is the other weekend, his cousin and best guy friends came over, his cousin was his best man at his wedding. They were talking for hours, just guy stuff, but then they start talking about the past, and the conversation leads into how one day back in 2003, my boyfriend caught his ex wife at a park, with some guy from a Pizza shop he used to go to. His cousin starts going on about how he also ran into her and he cursed out the guy she was with.

They were just talking nonstop about how she used him etc. And the thing is, they were talking about this like if it just happened yesterday and not 18 years ago.

So I went to the living room I said, wow again you’re talking about your ex wife. He replies, “yeah cause my cousin didn’t know” I was like your cousin doesn’t need to know about how you saw your ex wife in a park with another guy back in 2003. You have a new life and with a new person now. I told him, I don’t pay half the rent for you and your

This isn’t the first time I have overheard him and his cousin talking about their “past life”.

After his cousin left, I told him it is extremely disrespectful, why are you guys so obsessed with this woman, including your mom. You guys literally divorced in 2004. I told him the next time I hear him talking about her, we are officially breaking up.
I met the ex wife once at his sons wedding and she has a husband (the same man she cheated on my bf with and had a child out of wedlock by) her and him were all over each other when I met them so its clear that she moved on a long time ago.

I just am not sure how to deal with this situation. It seems like his family is severely obsessed with this woman. He claims that I am overreacting and that he has no interest in her. That just because he talks about her doesn’t mean he wants to be with her. I haven’t listed all of the situations that have happened because too much writing. At this point, Idk if I’m overreacting or if this is a red flag.