“Can CBT help with relationships?”

Certainly, it can. As we grow up, we generally get very poor, or no orientation to understanding other people. We do, however, pick up a whole bunch of poorly formed assumptions, ideas, theories, and expectations, as well as ineffective or counterproductive tactics and strategies that can cause problems in relationships of all kinds. CBT can be very useful for increasing our understanding and improve our skill in relating effectively to others.
I hope this is helpful.

See this link:
https://www.psychologytoday.com/us/blog/think-act-be/201703/8-ways-cbt-can-improve-your-relationship