Op, first of all, I understand abuse... the excuses on both sides, the wishes to change, the promises, how hard it is to escape etc... so please believe me when I say that pregnancy and leaving an abuser are THE most dangerous times for women living with/having experienced abuse.
Now you are pregnant again, you will be deemed to be at greater risk, as will your existing child. Once SS know you are pregnant they would be stupid to close your CIN case, giving the last "round" of violence was during pregnancy and less then a yr ago (this is NOT enough time for him to have changed his actions, especially as you are now - or still were - seeing him)
SS should be able to see that you nor he take the violence seriously and should move to escalate the CIN and put the new baby under one too.
You could also stand to lose both children as you have proved that you cannot keep either safe how.
Start off by being 100% honest with yourself ...and SS and do what you can do to keep at least one adult in your children's lives.
You have already not been truthful with us until pushed (started off with verbal/emotional, then added smashing things to finally admitting physical abuse) and in order to stand a change of keeping your babies, you owe them to be honest going forward.