How can I protect my assets from my husbands' ex wife?

Question Details:

I currently have a Will with my husband and my 2 children as beneficiaries. If my husband and I have our name jointly on things, i.e. car notes, second mortgage, time share, etc., if I die first, will his ex wife have the right to take a percentage for her children? If so, is there anything that I can do to prevent that from happening? Important Notice