Explicit images

So my current boyfriend has pictures of me , to be exact live ft images. I was fine with him having them up until a few months ago when I felt less respected . I asked him to delete them and he said No, and that they are his . How do I go about this ? How do I delete them ? I honestly just want a reset on trust and I feel dumb on sharing those just by his response . We are 20 &21 btw