What is the difference? Please xplain

I sent my SO a video of me playing with my tits, when he came in he said he loved it but I needed to delete it out of his and my phone.

What I don’t understand is why is it his friends can send him videos or pictures of porn stars playing with themselves and all that but won’t delete it out of his phone but when I send him something like that he tells me to delete it?!

Edit: we are both 29 this year and have been together for 11 years, the videos his friend sends are short snippets of porn videos. He told me he doesn’t know why his friends sends them because he doesn’t really care for them but he won’t delete them he leaves them in his messenger.

Also my SO doesn’t jerk off to them, he does find it weird to do it when his friend sends them to him, plus he doesn’t watch porn without me unless I’m gone it’s an agreement that we made. He has also told me this said friend will go around work showing everyone random porn videos, he doesn’t hang around him at work very much. He does find it weird and uncomfortable but he also says he thinks it’s normal for guys to send videos like that to each other!

EDIT: So I asked my brother if it was normal for guys to do that and he said it is, he’s even sent my SO video (I didn’t know that) and that he has friends that send him that stuff😬