How can I protect my assets from my husbands' ex wife?
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?
The ex-wife and her children would have no claim at all on your estate, none whatsoever, and it doesn't matter if you die before your husband or not, or whether you have a will or not.
If your husband dies first, all the joint assets become yours "by operation of law" at that time, whether or not there is a will and without probate, they never go into his estate, as long as you have set up the joint tenancy so there is survivorship. The ex's children can't touch any of that. The same happens if you die first, of course, the property all becomes your husband's.
There are two ways to keep the assets out of the ex's children's reach: one is for your husband to have a will that specifically disinherits those children. The other would be to put the assets into a trust (or matching husband-and-wife trusts) that is irrevocable, leaves the assets in your control during your life and then gives them to your children after both of you have passed on. This kind of arrangement has to be worded properly, but that's all in a day's work for a competent wills and trusts lawyer.