I will put on my two cents but I hope you could soon get a mans perspective,,, he is deleting it obviously cause he knows you do not like him looking at porn. And I would also guess porn is safer to look at than letting you down , or performing for you.
Who knows maybe guilt is eating him alive????
Anyhow do not take it personal and stay calm as you have been.
Dunno your sex life sitch much so I am just trying to fill in the blanks.......
Take care and God bless....