Is it permissible to lie for the sake of marriage, such as by claiming to be divorced, and am I sinful for what I said in this regard?

The fundamental rule concerning lying is its prohibition, except in specific cases such as reconciling disputants. As for outright lying, a Muslim is not excused for it unless they are a new convert to Islam. If you married a second time after your lie, you have combined deception with lying. Therefore, you must repent and seek forgiveness. It is not permissible to conceal a marriage to another woman from the one you intend to marry.