watching porn with SO?

I like porn, when i'm single. However, when I meet a man, I don't want them watching it as it makes me uncomfortable.... so I don't watch it either. however, I recently have considered watching porn with my boyfriend while we are together to spice things up. I just don't feel comfortable asking him if it was something he would want to do, since I am so against him watching it alone. Any advice on how to bring the subject up and make it light and fun?