I can speak only about Indiana law, which may differ from that in your state.
Generally, property inherited by one spouse stays w/that spouse if there is a divorce UNLESS the property was comingled.
What does that mean?
Say for example she inherited $10,000, and she put it in your joint checking account. Then money went in, money went out, and there's no way to tell what is what. That would be considered comingled and would be divided evenly.
In Indiana, if she inherited a cottage, the cottage itself would remain hers, but she could have to pay you half of the increase in value of the cottage between the time that she received it and the time of the divorce. If the two of you pumped a lot of marital money into the cottage to fix it up, you might have a stronger claim.
This is probably an overly simplified explanation of the basics.
Your best bet is to consult w/an attorney in your state.