I couldn’t agree more with nicoleflynn. I believe that yelling is abusive. I personally set a boundary with my BPD partner that he not yell.

Could your wife continue seeing this T, or another one, on her own? She could get the validation she needs that way. It would also put the focus on her instead of on you, and hopefully lead her to work on her own issues.

I read a book called “The High-Conflict Couple” that was fairly useful. You might want to give it a look. My BPD partner is very open to change and working on the relationship, though, so I don’t know whether it would work the same for you. Wishing you luck.