I think it would depend greatly on the details of the situation. Two questions come to mind when examining such a situation.
Why you don't get along? Is it a lack of common interests, or is it a genuine dislike? If it's the former, I'd say you have a better chance of have at least a civil relationship than if it was the later.
How close is your spouse-to-be with his or her parents? My cousin really loathes in his wife's parents. But, his wife isn't very fond of them either, so it doesn't put a strain on their relationship. If, however, his wife was very close with her parents, I could see the marriage unraveling almost as soon as it began.