My husband has found out he’s not my sons father what should I do?

He’s done a paternity test behind my back after suspicions and now he’s found everything out and I think my life is ruined.
He confronted me today. Said he didn’t know what to do. He didn’t want the embarrassment of people knowing but he doesn’t want to raise a child that is not his biologically. He’s wanting to get our other kids tested too.

The bio father doesn’t know. I think my husband might tell him. I’m worried they will team up and take me kids from me. I don’t know how to stop this. I’ll just do anything to keep my kids with me.

He’s told our beautiful boy all of this and my son is distraught. Shouted at me. I didn’t even think he was old enough to properly understand but he did. All our kids know. I feel like others will too. I’ll try stop that because I’m trying my hardest to minimise the chance of divorce.