Honestly idk anymore

So a girl I asked my boyfriend to block recently added him on snap,( she sent him revealing pics) he told me that she added him. I asked him if he wanted to add her back and he said yes, I then reminded him about the pics she sent last time and that I don’t want him to add her and he kept asking me why couldn’t he add her and that he wanted to saying stuff like

“It May happen” (him adding her)

“I won’t add her not yet”

“Come on she won’t send those pics again I’ll tell u if she does”

I told him it’s not about him telling me it’s about it happened once and who knows if it’ll happen again and that I don’t want to take that risk (I’ve also had problems w him w another girl who sent him pics, everytime we got Into an argument he would unblock her and start talking to her behind my back and I didn’t find out till months later)

She added him around 10 in the night and kept begging me to add her till around 2am than he proceeded to change his snap password so I couldn’t get in, I didn’t even go on his snap at all but he changed it so I couldn’t get in