Hi from Just Answer. I'm PDtax, and can assist. This happens a lot, and remedies are limited.
The first is agreement to amend the filed return and split the se income among both parties. if they filed joint, it won't change the tax, but will give her credit for some contributions.
Second is to consider how the contributions will be drawn on. If you represent the lower incomed spouse, she might be claiming a spousal benefit later on, and having her ex claim all the income will actually help, by increasing his wage base (and also hers).
If it really was a partnership, a review of the 1065 and k-1 filings is in order. if improperly filed, the divorce can order amendment of those returns, as a partnership has to allocate income between its partners. A review of the partnership agreement is appropriate here.
thanks for asking at Just Answer. Positive feedback is appreciated. I'm PDtax.