Is my ex entitled to more then half my pension at time of divorce?

Illinois is an "equitable division" state, not a 50/50 division state when it comes to property division.  It is possible under some circumstances for the court to order your wife to receive more than 50% of the marital portion of your pension (meaning 50% of the portion that accrued during the marriage vs. the total pension accrued).  It doesn't happen very often - most of the time, the court will order that she receive 50% of the marital portion.  The courts look at several factors when dividing property - assets, income, ability to continue to accrue income and assets, age, employment status, etc.  The court starts with the concept of a 50/50 division, but is one spouse has much more in assets or ability to earn much more income than the other party, the one with a lot less can get more than 50% of the marital assets.