<human>: First-time poster, hoping format isn't too horrendous.
I don't want to dwell too much on the 'relationship' side of things, I'm primarily seeking opinions/perspectives on his upkeep of a porn blog.

A guy I've been dating has a porn-dedicated tumblr. I'd like to think I'm open-minded, but coming out of a string of serious, monogamous relationships I wouldn't be surprised if I'm not as open-minded as I should be.

I haven't explored the blog in question very much - only on two occasions when he sent me content, and mostly it was basic porn gifs etc. But every so often he reblogged a candid/selfie of a girl with a caption about them being stunning/beautiful, or replied to an anon's sexual request etc.
This was far earlier in our dating phase, and I haven't looked since.

My main thought about it is that it is essentially a "brand" or perhaps an escape. Less so projecting his personal desires, and more venting his sexual desires.
I'm aware I'm probably naive, and have avoided the blog since as I am terrified that I could get jealous/insecure. I don't like to think I would, but I don't have any understanding of how deep his interactions with other tumblr girls/anons etc go, and once you've seen something, it can't be unseen/forgotten. 

I'm sure I'd communicate any issues I might have (as I said, I didn't want this to be about the relationship, more about my feelings towards his outlet), but for now I'm looking for people who might understand and provide insight into how I could handle or justify this in such a way that I can respect what he does and keep it separate from our interactions.

Can you give me a shortened version of the text?
<bot>: Guy I'm dating has porn tumblr with frequent reblogs of amatuer girls' photos. Would like to be understanding, perspective/insight on how to view this going forward is very appreciated.*