Am I being reasonable to leave

So my boyfriend of 3 years has what seems like a porn addiction but I don't agree with it at all...I keep telling him if i see it again I'm done...it hhets every tine but I keep on seeing it.He absolutely loves being sexual with me in person which I love and makes me feel attractive but when hes not I feel ugly and like I'm not as good as the other girls...we used to do it on video call now hes saying hed "rather wait" and sometimes we don't see eachother for a week or 2 and he claims he doesn't watch anything but I feel like hes been watching stuff or possibly having sex with other people and paying them...the only evidence of this I've seen is a screenshot of someone saying "okay but I don't want my kids to know just come in the back door and them talking about the exchange of a steam card and her adress.Nothing else tho..nothing about it happening.The message thread was gone...if I see porn again am I rediculous for leaving because alot of lther girls allow it or should I because hes disrespecting what I want...would any guy actually not watch porn because I didn't like it though honestly???