is porn cheating? HELP

so today i asked to borrow my boyfriends phone to see if our supermarket was closed or not and he was on pornhub. i honestly don’t understand. i give this man sex WHENEVER he wants it. i try my hardest to please him all the time. im 8 months pregnant and lately haven’t been wanting to give him head because it hurts to. but every damn time he wants sex even when im hurting i give it to him because i want to at least please him. and he would literally beg for head and apparently “joke” about going get it from another girl. wasn’t even a joke probably, he just said it was a joke because i got upset. anyways why isn’t it enough letting him get off through sex?? is it because i haven’t gave him head lately? when i first seen it he claimed his co-worker was on his phone. which made me more mad because even if that was true he has a bunch of my nudes and dirty pics in his camera roll. why would he be so irresponsible and let a co worker possibly see that? then he told me he lied (which i knew) but then said it’s only so he can learn ways to please me better?? HE HAS NEVER TRIED ANYTHING NEW AT ALL! and i don’t see how a porn video called “man fills big tits with cum” would teach him anything. if he truly wanted to learn he could have googled an article, not porn. it’s just one big lie! he’s an excuse that’s all he is that’s all i ever get. i don’t understand how someone could be so sexually ungrateful. he never makes me feel good, never makes me orgasm, nothing, tbh his sex don’t even feel good like i want it and i have NEVER complained and only worried about pleasing him. on top of that, im always so shy and unconfident about my body especially my boobs and he knew that but this makes it so much worse. i just don’t want to be with him anymore, if im not enough then he can go watch porn behind another girls back. i haven’t had feelings for him for the past three months so many this is time to end it? how do y’all feel about boyfriends/husbands watching porn?