New and desperate

Hey everyone, I'm a new member and I'd like to thank everyone in advance for their relpies and advice.

A little back story. I'm 28(male) and just got engaged to my fiancee who is 29 (female) and we've lived together for about 2 years. I've been watching or looking at porn pretty much every day since I was 13. Me and my fiancee since we've moved in together are usually only having sex like once a week. I have a physical job and work long hours and by the time we come home and make dinner, clean etc I just dont have the energy or drive to have sex. She's also the submissive type. She wants to feel like she's wanted so she never initiates sex so it's all up to me to initiate. Anyways, every once in a while she'll get angry over the fact we're not having a lot of sex and I sort of make the excuse that I'm tired. Little did she know I was looking at porn at work, at home I'd watch porn and masturbate before she got home from work (I get home earlier most days), and I'd watch porn and masturbate on my friday's off work while she's at work. Well she's pretty much fed up with that now. She accused me of cheating with other girls and that's why we're not having sex, which isn't true, I would never cheat on her, she does'nt deserve that and I love her dearly. Well the other night while I was sleeping, she went through my phone and saw all the porn I've been watching and freaked out. It was finally time to admit that I had a problem to her, as well as myself because up until that point, I didn't think I'd had a problem because it's always been part of my life and every guy watches porn right!?!?!? Anyway's, she's said she can't marry me if this continues, which I can't blame her for. Until last night, I had gone 3 days with no porn and no masturbation. I was excited to have sex with her last night until we began and I couldn't get an erection. I thought it would be the complete opposite since I hadn't orgasmed in 3 days!!! She started crying and think's it's her and that I'm not attracted to her. Have any of you guys experienced having erectile problems after quitting porn. I'm going to try and have sex again tonight and if it happens again I'm going to be very worried. I just don't know what to do.