BOYFRIEND's EX.... Advice please.

This is super long but My boyfriend and I have been dating for almost a year (we've known each other for longer) and are expecting our first child. I feel like we have a good relationship besides some issues with his ex. They had been broken up for around a year when him and I started dating but they were together for 7 years I believe. When we first started dating he told me that she cheated on him and was now with the guy she cheated on him with, he told me that he still kept in contact with her family and from what he told me about her I assumed he was not in contact with her. She still had a bunch of stuff at his house when we started dating and it was soooo annoying seeing it all of the time, he didn't get all of her stuff out until I moved in with him and made it clear I would not move in with all her stuff there. She also went to his house once to drop something off and he told me about it, after that I started wondering if they were taking so I asked him if they were and he told me they did a few times a week, I was not okay with this at all, I told him that if he was going to talk to her I didn't want to be with him. He told me that she expressed that she was sad he was in a new relationship and didn't really talk to him before finding out we were together. After a night of arguing I pretty much gave him an ultimatum he told her he wasn't going to talk to her anymore and as far as I know he hasn't. BUT I'm still so bothered that it even happened, he didn't want to stop talking to her because he fought with me about it and defended it, he kept all of her stuff there, pictures on Facebook, was even talking to her before me having to fight with him to be done with all of it. He also deleted all of their messages so I never really knew what they were talking about besides what he told me which I want to believe but It still bothers me. His family is still in contact with her and some of them even hang out with her and I feel like she just tries to hang around to bother me. I don't think she really talked to any of them still until she found out about him and I dating. It bothers me even more because she cheated on him and obviously didn't end the relationship in the right way and I feel like she is just trashy and can't be trusted. She continued to text my boyfriend after he told her that he wasn't going to talk to her, until he blocked her on everything! All of this while she is in another relationship. I feel so dumb and immature for letting this bother me, but it still does! I have always been a confident person until my previous relationship (which was abusive) and I don't know if it's just my insecurities or why I'm SO bothered by it. It seems like she is the only thing we fight about and sometimes I just don't even want to deal with it anymore and feel like I'll never be over it. I don't know how to let it go. I really do believe that he doesn't talk to her anymore but I'm still so hurt by the way he acted when we first started dating. We don't fight about it as much but I still get so upset when we do and he is just sick of hearing about it but I feel like I constantly need reassurance because of the way he did act before and he doesn't give that to me. Any advice or thoughts? Would any of you ladies be annoyed by this?