Help!!!! So angry and confused!

I really don't know where to start. My partner and I have always been quite experimental and we both have high sex drives, but recently we haven't been doing it a lot. He has back problems so sometimes we can't, but I've just found that he's been watching porn while I'm at work. I'm completely fine with that, but he hasn't told me about it (we've always been very open) and he keeps telling me he's not in the mood. Also, in the past he's made me feel awful for watching porn by myself.