Threats to tell my parents and little sisters

I’m currently 8 weeks pregnant with me and my ex’s 2nd (well together, he has 2 others.) He ended up catching herpes and not knowing while we were broken up for quiet some time. We got back together and sure enough he passed it to me.

He’s on my phone plan and I’m constantly on his ass to pay the bill. He thinks it’s okay to be a few days, a week, even a month late as long as he pays it. I’m tired of stressing about it and we aren’t together and barely talk so i told him he has until this Saturday (but i told him last week, giving him two weeks) to find someone else’s plan to go on to or to get his own. He said okay thanks for the week.

Now all of a sudden he’s threatening me about it. He’s telling me if i shut his phone off, he’s going to message my mom, my dad, and my two little sisters (ages 11 and 13) that i have herpes. My family absolutely HATES him and i know if i tell them he’s making that up just to hurt me and make my life hard they’ll believe me. But its just the fact I’m scared they’ll always wonder in the back of their heads, and that’s embarrassing. I don’t want them knowing. Is there any way he can get into legal trouble from this? I don’t think he can but i was just curious bc i know some things done out of revenge can get you into trouble.