How do I get my fianc? to understand that pied is real and not just some excuse

I just recently learned that I have suffered from pied and the effects of it has left my relationship destroyed. My fianc? knew something was wrong with me because I seem distant and not sexual towards her. Before we met, I was expierencing sever ed and I was extremely addicted to porn, but I never made the connection between the two. But when I met her my ed went away immediately bc she turned me on more than anyone else ever. But I still struggled to initiate sex and when we did have sex it took me forever to climax. I still watched porn but I finally decided to stop watching it after the numerous times she found out from my browser history. I kept promising I wouldn't watch it again but I relapsed a few times in the last few months. She feels like I don't want her and that I really want the kind of girls I view on porn which are a completely different body type from hers. How do I get her to understand that I do love her and that I do love our sex?? Nothing I say is convincing her I need help!