Legal Question in Wills and Trusts in California

I do not know anything about Irish will law, but a will is separate from marriage. The Will would deal, in the US, only with the person's own private property so marriage would have no effect.

Your marriage in California may create some community property rights for each spouse for property acquired during the marriage, but there are additional issues concerning how title to property is held, etc... that cannot be answered without knowing the specific facts of your situation. You should meet with an attorney and go over your situation in greater detail.