You generally are ONLY entitled to half of whatever portion accrued DURING the marriage. Which may not be 50%- especially if he has many more years accrual left before retirement, or many prior to marriage.
Those funds would be received when the program considers it payable. Most of our pensions do not get paid until we meet the criteria for receipt, which means achieving whatever the plan's set of requirements may be. Additionally, he'd be entitled to half of whatever you accrued in your retirement plans during the marriage.
You and he also share the marital debt.