If real sex / touch triggers him with memories of abuse, it may feel safer to him to use porn. Especially if in his triggered state he might be unable to perform and fears embarrassing himself and disappointing you.
But since the situation isn't changing, it is clear the porn isn't helping.
However... him wanting to open up the relationship to other women seems to contradict that, since it's more touch / sex. Then again, lots of guys have those desires, it's just that most know well enough to keep their mouths shut! He may have voiced what is a "normal" male secret desire due to a lack of proper inhibitions / limits created by the SA.
The hundreds and hundreds of pictures thing is not specific to him... when you watch enough porn, that is explicit enough, for long enough, you start to need to see the action take place faster, with more variety. That's why one of the most popular formats in online porn recently is "compilation" vids, each an hour or more but made of hundreds of spliced together vignettes just a few seconds each. There have been articles describing this. If taken as part of an otherwise satisfying relationship, then it doesn't mean anything except that he's seen somewhat more porn than average and gotten desensitized to it. But... if he's way too "hands off" concerning you, then it's just another symptom of the underlying problem.
At the risk of sounding corny, have you tried a "date night" but with slightly more "pre-sexual" and "semi-sexual" behavior than is usually socially acceptable? Make subtle innuendo remarks, talk about what youd like to do and where, text him pictures or promises... show him that you're better and more exciting than some 2-D pixel girl. Just a suggestion - it might create a porn-ish atmosphere in his mind, if that's what he needs.
I must say that even as a hypersexual and pro-porn guy, even I think the above suggestion ought to be beneath your dignity - because it's being done out of desperation to entice him after he keeps neglecting you. He's really not treating you right but you know why. The above suggestion just might reset your presence onto his wavelength... and then hopefully lay groundwork for the relationship to get more casual, natural, and unscripted.
Sorry if it sounds dumb, it's the only thing I can think of to help.
"Don't think it hasn't been a little slice of heaven just because it hasn't!" --Bugs Bunny