u/Anxious-Theme9825

I've been with my gf for 1 year , everything is good and smooth , but one thing that keeps bothering me is sometimes once a week she mentions her ex , not comparing me to him , for example today we were talking about technology in our old schools and she suddenly mentioned that her ex's old school was way ahead of others, all of the mentioning are close to what happened today .
I talked to her about it in the past and she briefly stopped but now i feel like she mentions him once in a while . Any advice?