Porn Anxiety/Insecurity?

I know this topic has been discussed so many times before, but I just don't know what to do. The thought of my SO watching porn just gives me really bad anxiety. It's one of my worst triggers now and I have no idea why. We already talked about it a few times before, and the thing is that he doesn't even watch it (since he found out that it makes me feel bad), so I don't know why it makes me feel so badly. I have never even thought twice about porn in relationships until this year when it almost gave me an anxiety attack. It's just that whenever I see a post about porn, or even just think about him watching it, my stomach churns and it gets a little hard to breathe. I hate feeling bad about this. I don't consider porn to be cheating (but have nothing against the people that do), so it's just really odd to me. This year I've also had a problem with jealousy and some insecurity, so I'm wondering if I'm just jealous of him possibly looking at other women in that way. Does anyone else feel the same way? Also are there any tips on raising self confidence? Because my self esteem has been low all year.

And to the people that don't think porn is a problem at all, that's great that it works for your relationship, but there's no need to bash other women for the way they feel (not saying that you all bash, but there are some that tend to invalidate other people's feelings). I wish it would work for mine, but for right now it doesn't, and I'm trying to feel better about it so it doesn't give me anxiety in the future.