Hurt-advice needed

So I’ve been with my ex for a year. I know for sure that he is the one. As cliche as it may sound, I’ve felt things with him that I’ve never felt before. And mind you I’m older, so I’ve dated plenty and have even been engaged.

Anyways, my boyfriend was in a long term relationship prior to me. Him and his ex no longer speak but his family is really attached to her. I knew this coming into the relationship but since then. I’ve come to be really close to his family and they adore me. BUT I had a feeling that his ex was still in the picture as far as still being close with the family. It hurts but I’ve told myself that with time maybe that will stop.

Last night i was having casual conversation with his sisters, she straight up told me that the relationship they have with his ex is never going to change and she will always be there. Like I said before, i had a feeling they still talked and hung out with her but to actually hear it come out of her mouth and to know that she will ALWAYS be in the picture , REALLY hurts... a lot.

My ex and her don’t have kids, they were never married...they have zero ties. So I’m just confused as to why they chose to keep her around.

Someone please help. Am i making more of this than I should ?