Am I overreacting ?

Okay so my boyfriend has a son from a previous relationship , and I absolutely love him. But his mother is a different story. She stalks my account, slashed his tires when she found out about me, threatened to take his son to a different state, talks badly about me , etc.

My boyfriend and I have a four month old daughter. I kept my pregnancy a secret for many reasons. One being severe prenatal complications where there was a good chance baby wouldn’t make it. So his ex didn’t find out until after the fact . No one knew until after I gave birth and posted

Anyway I noticed this random account seeing my stories so I clicked on the account and see that it’s his “baby mamas” best friend who is also her neighbor. It made me uncomfortable so I blocked her. But before I did, I noticed that my boyfriend was following her and her back. It makes me uncomfortable knowing that because if his ex is having her check up on my page I feel like she does the same to his. And he said they weren’t close, he only knew her through his ex. Also when she found out about my daughter she would drive past my house with this friend.

I told him I don’t see why he would want her following him or still having that tie to his ex because it’s clear she asks her to check our pages and its just drama. I told him I was uncomfortable, I didn’t get crazy or mad. I just expressed my concerns calmly. Nor did I ask him to unfollow her. But he got defensive and angry, and just walked out the room. Now he’s not speaking to me.

Am I overreacting? If I am, I’ll let it go but to me it just seems very weird that he has this friend of hers on social media