Do tell your support worker first, darling. There’s an awful lot to think about. A child means potentially having the abuser with a foot in the door for the next twenty years or more. That’s why they often force risky situations even of you don’t want a baby.
The choice is yours, even the choice of telling him or not. Be very careful who you do tell as it could get back to him.
Huge hugs,
Flower x