Typically, since Michigan is a No-Fault Divorce state, the spouse is entitled to 1/2 of the marital assets upon divorce. There are factors for the court to consider in shifting the asset division into bigger or smaller shares, but generally speaking, it's 50/50.
In your case, we have a short term marriage and we should only look at the value of the asset during that short marital period. Whether we are talking about the house, the 401K or any other major asset, we need to know a couple things. One: the value of the asset on the date of marriage, and two: its value today.
Why? Because you are really only going to have an argument for 1/2 of the appreciation of the asset during the course of the marriage. If, on the day you married, the 401K was $110K, and today it's worth $115K, then there is only a 5k appreciation in the asset and you would be entitled to 1/2 of that amount. Typically, you need a Qualified Domestic Relations Order [QDRO] to split any portion of a 401K from one spouse to the other.
If the 401K has gone down in value since the date of marriage, then you have no claim against it's current value. Keep in mind that I'm speaking in very broad and general terms here, but these are the basic concepts. I would guess that due to the length of the marriage in particular, the value of the marital estate is small and there isn't going to be alot to divide between you and your spouse.
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