What should i do

I posted a poll before about if it was wrong of me to ask my bf to cut his friend off. For good reasons of him calling me names/etc & disrespecting me in the past the majority of votes said no I'm not wrong for asking. He said he was willing to do so but that friend keeps texting him, & my bf deleted bits & parts of the messages....he said he didn't want me to see them because i wouldn't believe he cut him off? But how am i supposed to believe him if he deleted the messages....i don't really trust him he deletes his messages like all the time...