@JGH59 , IRC section 163 (h)3(B) and following subsections deal with acquisition indebtedness, interest thereon, qualified residences etc. The use always is aggregate indebtedness , main-residence and ONE other chose by the taxpayer. Thus for the year 2024 interest deduction is on aggregate indebtedness of 750,000 for a joint filer or 375,000 for single or MFS filer.
Therefore you get to choose which 2nd home is part of your qualified residence.
My reading also does not preclude each MFS filer having a separate / different 2nd home.
Perhaps , you should consult a tax professional especially if the interest deduction warrants the cost/effort.
