If he puts you on the deed, then the asset and the income earned from it is marital.

There is some debate that it only starts from the point of marriage when the name is added to the deed. But even if it did start then, some of the equity would be subject to distribution.

If he doesn't put you on the deed, it's completely separate. Unless you use marital funds to do major repairs to it, then some of the equity would be up for distribution. But if the house generates enough income to cover the major repairs, then it's not. And if he puts the income that it generates into a separate account, then any savings and interest from that would be separate.

Your best bet is to consult with an attorney about all possible scenarios regarding the premarital assets.