Boyfriend and porn?

Chelsea 🌻 • 7/20/15 - Olivia Kate, my heart 💓
A little background - my boyfriend and I have been dating for almost two years and were best friends two years prior to dating. 
I personally don't mind if my boyfriend watches porn as long as it's not excessive where it could be considered an addiction. But this passed summer we went to North Carolina with his family. I woke up and rolled over and saw that he was on a porn site. I was so hurt because I was sleeping right next to him. I confronted him about it and when he realized how much he hurt me, he was crushed. He felt so bad and apologized over and over. I definitely felt he was sorry and it wasn't at all because he got caught. He felt horrible because his actions hurt me and his "stupidity" and "lack of concern/respect for my feelings and how it would effect me" (his words). I told him I don't mind that he watches it every now and then as long as it's not an obsession and that he doesn't do it when I'm around. He completely understood and still apologized and made sure I was okay and said he is not addicted to it and does not have a problem. 
I asked him why he did it. He said he checks a porn site he goes to often and not necessarily to get aroused. I didn't understand why. He said that it helps him get ideas on positions and techniques etc. I let it go and trusted him about it. 
Often I don't have my phone and need to use his to google something. I don't even purposely try to find anything and when I go to the search bar, his recent searches drop down. I'll see (for example) a horror movie he googled, an article on something in history, and then xvideos. Almost all the time it always comes up. He clears his safari history often now and I don't know when he actually watches or searches porn. I think he clears it because he's ashamed but I DID say I don't have a problem with it if it's not out of control or when I'm next to him! 
My concern is that he is addicted to it. Our sex life is healthy for us by the way - at least twice a week (we work a lot) but I'm worried because I want to help him (if help is needed).
How often does your significant other watch porn if any? And when is it too much to where it's an issue?