Life bullies

I have been divorced for 6 years i still have children with my ex. My ex left me for another woman and they are still together. We have 4 children together and the kids go to their place every other week . The person he left me for has continued to bad mouth me to my children and has came to my workplace and harassed me and my son. We both work the same place. I do not respond to any texts or calls that try to stir up drama from them. I have been keeping to myself the best I can with a boyfriend of three year now. It just really hurts when my children come home and tell me all the bad things she says and it hurts them also.