I need legal help

My husband's ex is constantly harassing us. She stalks us on Facebook and is always trying to cause problems. We are always nice to her and the only thing I can figure her problem is is that we're happy and she's not. But recently she tested him saying "if he even thinks about reproducing" she's taking him back to court to get more child support. What can we do? I'm 3 months pregnant (she doesn't know) and we wanted to tell the kids but not if it's going to cause problems.