should i tell him?

I’m 21, i have a 3 yr old son. His father & i are not together and haven’t been since he was born. My boyfriend & i have been together for 2 years now. Well in the beginning he supported my son financially and sometimes interacted with him. Not much. Like went swimming with us. Did family things! it was usually just me. Well now he doesn’t help financially, all he does when he comes home from work is play on his phone, play his video games, or watch tv. He doesn’t ask me how my day went at work or nothing. He told me once he leaves work, he wants to leave and doesn’t give a fuck about my work. The one day we got into an argument, he screamed shut the fuck up to me. He is sometimes disrespectful to me. He tells me how to parent my son, that i need to spank him all the time. Well, i just found out that i’m pregnant. I’m so lost, emotionally and physically scared. I dont know what to do because i was literally just about to end things with him. I dont know if i should wait to tell him until i go to the doctor to surely confirm it, or just tell him now. I dont know what to do. i’m still super early like 4 weeks. I found out so early because i was throwing up and never did with my son. i’m just scared.