I saw him watching porn

Let me start by saying I'm not against it. I know he watches it. I don't care that he does. Having sex is really uncomfortable and it hurts me so we don't do it often. I'm 28 weeks pregnant. 
This morning I got a call about our puppy who has been at the vet for almost a week because she was really sick and I jumped out of bed because I didn't have much time I get her. I run into the living room to put clothes on and he was beating himself off to porn. I don't care that he does it. I just don't want to see it. 
It really upset me this morning and I feel ugly and disgusting. Wasn't expecting to feel this way... Especially when I know he does and don't care. 
Don't bother responding if you are going to judge me for my choices in my marriage. Not posting for judgement. Just needed to vent