are taxes due after I assumed the mortgage of my ex boyfriend?

Asking for a friend:

 

"10 years ago I bought a house with a mortgage with my (now ex) boyfriend. We used to pay 50% mortgage each every month.

Last year we split up and I assumed the mortgage and I bought him out.

I still live in this house which is my only residence.

 

What tax implications does this have?

Do I need to pay/deduct anything?

 

thanks!"