I am not sure about being in my best friend’s wedding if she’s inviting my ex

My ex husband and I (f42, m42) separated a year ago after two-three years of fighting over children. I had an abortion and he took it very hard and our relationship never recovered from it. He changed his mind and said that he wanted children. I think he hated me and he just up and left one day when I was visiting my parents and came home to an empty apartment and I found out that he was seeing someone who was pregnant. He has a year old son now.

I found out that I was pregnant about 2 months ago. My best friend is getting married in may and I am the moh. I will be 29 weeks pregnant. Now she said she invited my ex and his partner. I told her that I don’t think this was a good idea because her wedding should only be about her but she seems to be very fine with everything. Now I am bot sure I want to be in the wedding but this will make everyone hate me if I declined going to my best friend’s wedding.

At least someone needs to tell my ex about it because while I know he is happy now. He still sends me texts sometimes like we are still together. I never answered but sometimes it feels like he sends me a text or a picture or an inside joke like he’s forgotten we aren’t together anymore.

We have been together for 25 years until he left. I don’t know, thank you for listening I am just venting about my feelings and my hormones are all over the place