hi - thank you for your lovely message. it made me feel less alone today

not unlike a lot of other people with BPD he has significant issues surrounding impulse control and sex. to my knowledge he has not been unfaithful, but a lot of what he has done has centered around excessive use of porn. without getting into too many details, he has done a lot of this behind my back and without me knowing. we have had many discussions about boundaries around this, and what healthy concepts of sex and intimacy can look like. basically, when going through his phone, i found evidence that he had violated one of the boundaries we had laid out. Sorry i'm still being vague - this is my first post and i am still trying to get comfortable with laying this all out on the internet!
also - to clarify, we are in couples counselling and the counselor suggested, given how a lot of his issues stem from lying and hiding things (particularly things he does on his phone) that a way for us to build up trust again is for me to be able to freely access his phone and witness that he is being trustworthy.
re:figuring out my own boundaries, i have come to the realization recently that i am this is something i am really going to have to work on. i welcome any suggestions or tips from other who have had to do this work too!