I was married to a military spouse for 26 years. We got divorced about 4 months ago. Can I request now half of military retirement?

It may be too late.  The job of the divorce court is to divide all the assets earned during the marriage by either party according to a "just and right" division.  Retirement earned during the marriage is such an asset.  If the divorce decree awarded him his miitary retirement, you are likely precluded from getting the division redone.   If the military retirement was not divided, then you can go back to court and ask the court to divide the asset that was not divided in the divorce.   You will probably need to have an attorney revew the specific language in the decree to determine which category the retired pay fits in--and you need to ensure you have have a lawyer experienced with military issues.