Guy friend keeps trying to escape the friend zone

So there's this guy we're really close we've been close friends for almost a decade. He's been ready to take our relationship to the next level but I'm not attracted to him in no way, shape or form. So on my end it'll never work I have expressed this to him yet he's still persistent and always asks me about my relationship and gets mad about what I tell him. For example when I found out I was pregnant with baby #3 I told him and he got angry. I really don't understand why he is forcing the issue when I'm not budging even if I wasn't in a relationship. He claims to have a bad feeling about my on and off again boyfriend but we have two kids together no real problems. Little stuff are big stuff with us but we're working everything out and when we found out we were pregnant again it brought us closer. His jealousy is really annoying me. He takes shots at me on Facebook and he's not there as my friend anymore. It feels like he wants force me in a relationship or something. The news of my third pregnancy shattered his dreams when he never had a chance with me to begin with. What should I do?