Boyfriend uninterested sexually

I'm 29 weeks pregnant and my boyfriend told me tonight he is less attracted to me than before. He tried to make it better by saying he thinks I'm "cute and adorable" while pregnant but not sexy... We have barely had any sex or anything for the past two months and when we do, he doesn't take the time to let me warm up to it so it never ends fun for me. He has been watching a lot of porn lately and I have been getting jealous, insecure, and very aggravated about it. Why can he spend 20 minutes doing that but can't spend more than a few to make me feel good?? Now that he told me he doesn't find me sexy I feel very betrayed about the porn habits. I know I might be over-sensitive but I don't think I should be put on the back burner and it's not fair.