You did not indicate which state you are located in. In a community property state or an equitable distribution state such as New York, you would be entitled to approximately one-half of the value of the house, and your husband would not have a right to ask you to leave. If you purchased a house while you are still legally married, your husband would have an interest in such a house.
You should wait until you have entered into a legal separation or filed a summons and complaint in divorce before you purchase any additional property.
I strongly suggest that you consider mediation to settle your separation and divorce, and if you are located in the New York City metropolitan area, please call me at 212-370-1660.
Leonard M. Weiner, Esq/Divorce Solutions