Why would my boyfriend remove these videos?

It's quite possible that the long distance relationship isn't working out for him. He might be finding himself feeling, perhaps, uncomfortable with or less inclined towards the sexy, physical side or your relationship, because of the length of time since you were last actually, physically together. You could be right about the possibility of breaking up, in which case you might want to be a little less intense with your pic/vid sharing, and leave the onus on him.