AITA for wanting to watch porn?

Last night (M)y long term girl(F)riend and I were in bed. I was interest in having sex but she had said that she wasn’t feeling it. I then asked asked if she was okay with me just masturbating because I was still in heat and of course didn’t want to make her uncomfortable. She said it was cool so I grabbed my phone to pull up some NSFW subreddits and get going. As soon as she realized I was going to look at some porn gifs she let out a disappointed “hhmmppff” . When I asked why she did that she told me she thought it was wrong of me to want to watch porn when she was right next to me. She wanted me to use my imagination, and think about her to jerk off while she was going to sleep. I thought that was sort of weird. I used porn a lot when we had been long distance and it became commonplace for me when masturbating. It’s clear she seemed to think of it as emotion cheating of some sort but I see it more as primal than emotional and don’t think jacking off to porn with her there should be immoral. She made me feel bad about how I masturbate and now it’s bugging me. Can y’all let me know who the A****** is?

Edit: Many of you find the issue to be the action of masturbating next to my significant other. She has encouraged me to do so in the past and that is why I asked her if it was okay to do it once more. The point of friction was not masturbating in bed with her but purely the use of NSFW material while she was there.