no easy way to split - even pro software does not have a feature like this
about the only alternative is to report summary totals for 1/2 the Long term items and 1/2 for the short-term items.
then you make 2 copies of the 1099-B and show on it where there are totals for short-term and long-term write in less 1/2 to spouse SSN XXX-XX-XXXX for one spouse and then the same for the other spouse. show the actual amounts being subtracted for each column.
then you use form 8453 to submit each copy of the 1099-B
https://www.irs.gov/pub/irs-pdf/f8453.pdf
read the instructions for timely filing
no guarantees this will work. the 1099-B is submitted to the iRS using only 1 SSN. so there is a possibility you'll get a notice because the gross proceeds reported won't match what the iRS has.
