Can you claim the First Time Home Buyer Tax Credit if bought out ex-spouse in matrimonial home following separation?

Turbo-tax questions are confusing to me. To qualify they ask did you live in "another" home that was your principal residence. Technically no, all the same matrimonial home.

Investors and rental owners

No, if you already owned a portion of a home, then you can't claim the First Time Home Buyer's Tax Credit when buying out the other owner.