I'm glad you are standing up for yourself (and your kids). Dont let her bully you. Your kids are the MOST important thing right now. Make decisions based on what is best for them; not what is best for you or your W.
Me: 48 y/o W: 47 y/o Together: > 20 yrs BD: Dec '15, then S 2nd BD: Mar '16, then I filed for D April '16: started piecing