Concerned don't know what to do now

My boyfriend and I dated previously about five years ago. We each made our lives after we broke up and now we are back together. My baby is 8 months old and from my previous relationship he was with me throughout my pregnancy and delivery my daughters father and was every before she was born he didn't hear his child and now he wants to help out with any payment just want to see my boyfriend everything care of everything for her everything she needs that she is his daughter. And we are having a baby together not sure yet whether it is a boy or a girl excited. However, his ex is now becoming pressure issue in our life's she calls him even when he changed he number. He told me the story with her she was pregnant with his baby and under five months she had a miscarriage get a car accident after that she does not find out that she can never have kids again from the damage in the car accident and she's trying to takeout on me and I have a boyfriend she doesn't know yet that I'm pregnant because his friends are trying to protect me because every time I do something but she sees my daughter and him on Facebook and is going crazy messaging me and he won't do anything about it. I am 4months pregnantand feel so upset I don't even want to see him. What should I do I love him so much but I can't hand crazy right now.