I don?t think you?re being unreasonable at all.
You set down some ?ground rules? which I?m assuming he agreed to? E.g. he said ?That?s fine, I won?t look at porn?
When I have started new relationships ? both my partner and I tend to establish ?ground rules? of what?s acceptable to us and what?s not. At this point, if we don?t agree with what the other is saying, I know we?re not compatible over intrinsic beliefs, so the relationship doesn't go any further.
The fact that your partner must have agreed to not look at porn and then did it ? 10 times, suggests he has absolutely no respect for you whatsoever and despite the people on here saying ?You?re overreacting? that?s their opinion on porn and whilst they are entitled to it ? The fact your partner agreed to NOT do something and then did it again, and again, and again despite knowing your feelings towards his actions doesn't suggest he really cares for your feelings at all.
The problem is ? You?ve obviously discovered porn before and you took him back. Then you discovered it again, and took him back, therefore whilst you?ve been saying ?This is unacceptable behaviour?, your actions are saying ?I might be mad with you, however after a while I?ll forgive you and let you back?, therefore why would he assume anything would be different this time around? All he has to do is wait it out a few days and you?ll give in as that?s what he?s used to.
I personally wouldn?t be with someone like this as I had an ex partner who was obsessed with porn and like you, I forgave him, only for him to do exactly the same thing again. I had this ?gut? feeling he hadn?t respected my wishes and when confronted with the evidence, we split up ? I wasn?t married to him and didn?t have children so the situation was much ?easier?, than yours, however I don?t regret it for a second as it meant I wasn?t constantly worried about him looking at porn and ?catching? him at it.
If it?s a deal breaker to you (and it would be to me, too) then yes, you need to go through with it and find someone who actually does respect your wishes.
I?m sorry you?re going through this.