My husband of 4 years just died two weeks ago. I am the beneficiary of his life insurance but not the beneficiary of his pension. The pension beneficiary was last updated in 2007; Phil and I were married in 2008. His two children ages 19 and 24 are the beneficiaries. Can I dispute this? I really need some help in this dark time of my life.

Very sorry for your loss. All depends on the written procedures of the pension system and law but in my pension agreement/system, there would be no relief- the most recently processed beneficiary designation would control the distribution. Our employees were warned of that fact very often and were warned of the consequences of not updating beneficiary forms when we determined that a change was warranted.
For instance, we were cautioned not to list more than one primary beneficiary. Some had listed a spouse and child as primary beneficiaries, which resulted in the spouse receiving 50% and the child 50%, while the employee may have intended that the child only receive the benefit if the spouse did not survive. A contingent beneficiary was to be designated in that circumstance.