I was a housewife throughout my marriage. My husband is wealthy. Will I get half of the assets?

Theoretically, New York is an equitable distribution state. That means that, as most New York Divorce Lawyers will tell you, you are entitled to your “equitable” share of the marital res. But what does equitable mean? That depends on the case and the circumstances. It is very case-specific. What is equitable for one person is not necessarily going to be deemed equitable for another person.
In the case of high net worth individuals, with incomes in excess of 300K per year, for example, and a seven figure net worth, equitable is probably not going to mean exactly fifty fifty. In theory it should. But it usually does not boil down to that. Especially when only one spouse is responsible for building the wealth. Don’t get me wrong, the New York courts are moving towards a fifty fifty split more and more. But even with a fifty fifity ruling, it seems that many wives are having a hard time collecting 50% given that their husbands have become better at moving assets abroad, outside the reach of the jurisdiction of the New York divorce courts, and into off shore trusts in tax haven such as the Bahamas, Switzerland and Antigua, and making it very difficult for the wives to get her hands on these assets.
More often than not, the parties are going to reach a settlement to make the headaches go away, and the wife is likely going to accept something less than fifty percent. Something fair, to reflect her contribution as home-maker, lover, mother, confidante, etc., but likely not fifty percent.
If the wife has signed a pre-nup that gives her even less than what she could have reasonably negotiated in a settlement, she is likely stuck. Unless the pre-nup was offered as a shot gun take it or I don’t marry kind of thing.
As a general rule, if you are the non-monied spouse getting divorced in New York, even if you had a “lengthy marriage,” don’t bank on exactly 50% of the marital res. You are unlikely to get that.