tired of my baby daddy

I started dating someone new (been together for 5 months) he's met my son and enjoys playing with him (I felt the need to allow him to meet my son early incase they wouldn't get along etc) and I've kept it rather private from my ex, all I've told him is that I've started dating someone new and that he has met our son.. I feel as though we have a child together that we aren't required to have other conversations about anything other than our son..

I blocked my ex on all social media but today my ex told me he searched me and went off about two photos I posted (they have my BF in it with my son (one of us at Disney land and one of my current boyfriend and my son asleep cuddling).. He keeps messaging me stuff like "how dare you allow him to stay over", "how dare you move on before me, I'm dating a new girl now she can meet him, how will you like that slut?", "I can see you never cared, you moved on so quickly".. Mutual friends we have showed me a post where he's trying to belittle me and what seems like to convince others that I've been the villian throughout it all.

I'm trying to be mature about it, to not retaliate but I'm so over it, anyone have advice for this situation ?