My ex and I separated Apr 2023. He owned the home we lived in, I was not on title or the mortgage. I bought a condo Jul 2023. Can I claim the Home Buyers Tax Credit?

No. As per the CRA:

 

Line 31270 – Home buyers' amount
You can claim up to $10,000 for the purchase of a qualifying home in 2023 if both of the following apply:

• You (or your spouse or common-law partner) acquired a qualifying home
• You did not live in another home inside or outside Canada that you (or your spouse or common-law partner) owned in the year of acquisition or in any of the four preceding years (first-time home buyer)

 

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/deductions-credits-expenses/line-31270-home-buyers-amount.html