need some advice on what to do

my boyfriend use to use twitter to watch porn and i didn’t like it but he seemed very understanding and said he would delete it. well he kept redownloading it behind my back and i confronted him about it and he promised he wouldn’t ever redownload it again but literally a couple minutes ago, i was just on his phone (not snooping, he lets me watch tiktok on his phone) but recommend apps came up and he had redownloaded twitter. what do i do. he promised he wouldn’t redownload it. this is the forth time this has happened