I am the custodial parent. Am I allowed to take out a life insurance policy on my ex for the purpose of covering child support in case my ex died prior to the children reaching 18, without my ex’s consent?
No, you must have consent.
Is there anything I can do then to protect the support owed in the even of my ex’s death? Is that something that social security will pay if my ex were to die prior to the children reaching the age of 18?
Your child may be entitled to Social Security benefits in the event of the other parents death. To learn more visit the SSA website. http://www.ssa.gov