Yes, you may be able to buy life insurance eon your ex-husband.

If you have an "Insurable Interest" you may purchase life insurance on your ex-husband. 

That would probably mean that he is responsible for child support or alimony payments to you based on your divorce agreement. 

While buying life insurance on another person requires his cooperation that cooperation can be ordered by the court. 

You should be the life owner, payer and beneficiary of the life insurance policy. T...