Is Porn Cheating?

I haven't caught my boyfriend in the act yet, but since I've been going to nursing school full time and working part time my sex drive has plummeted due to all the stress, and my friend had jokingly said that I should put aside time for sex or he will resort to porn. So...my question is if your SO was caught watching porn would you consider it cheating? I have thought about this and I have been neglectful initimatly to where I would understand why he would and I also like to read romance books and have read the trilogy of 50 shades of grey, is that comparable to men watching porn? Should I even be upset if I was in that position or would it be hypocritical?