I need opinions please

So, me and my fiancé have been together for 7 years and we have 2 kids. We are both in our 20’s. We have never had any major problems in the bedroom. At the beginning of our relationship we had a little trouble with him watching dirty videos on his phone. We talked about it and had an agreement. So, that hasn’t been an issue. We have always been good at mixing things up so that the same thing over and over doesn’t get boring also. We have our “alone time” at the least once a week, most of the time twice, sometimes more. Well, starting last week my fiancé said he wanted to get the kids to bed so me and him could have some “alone time.” We started messing around and he couldn’t get an erection. We tried for 4 hours and then just gave up. Keep in mind that he is the one who said he wanted to have our “alone time.” We both agreed we would try again another time. Of course, I was asking questions afterward.. I asked him if maybe he had got off by himself, he said no. I asked him if maybe I did something wrong, he said no. I asked him if he was worrying about something or anything that would make him not be able to have an erection, he said no. He told me that he had no idea what was going on and that if it was me or something that I did he would tell me. He told me that it really worried him because, that has never happened before. He acted like he normally does when we have our “alone time” and he put in a lot of effort, so I know he actually wanted to. Well, last night he wanted to try again. I had a week to think about it and I thought maybe I should spice things up a little more. So I took my shower, put on his favorite color lingerie that he likes on me, and put makeup on. Before anyone says anything about me putting makeup on and stuff, I did it to make things different because we have 2 kids so I obviously don’t get dressed up and put makeup on too much. Anyways, we tried again and the same thing. He tried everything and so did I. I told him maybe watch a video on his phone (just because it was something different.) He did finally get an erection but he could not keep it. We tried well over 4 hours again and agreed to stop trying. He swears on everything that he doesn’t know what’s going on and says that it scares him. For some reason all I can think about is am I the reason, maybe he’s getting tired of me? He tells me I look good a lot but, I feel like it’s only when he wants to do something. I don’t know I just can’t stop wondering about it. And it hurts my feelings that the video helped him for a few minutes but, I couldn’t even do that.. I am already insecure over my body, because I’ve had 2 c-sections. I try not to show that I’m insecure over my body because, he says he doesn’t like when I down myself and that it’s sexier if I own my body and show that I know I’m beautiful. He tells me that he loves my body and that I should be proud of my stretch marks because, they were made because of our kids. It’s just that I know that I don’t look like the women in those videos and maybe the way I look just isn’t good enough for him anymore. I don’t know this just makes me feel more insecure and my heart hurts so bad.

Does anyone know maybe what could be wrong? Or have any advice?

Thank you in advance!

I want to add also that no he isn’t cheating, he doesn’t have time to cheat. He goes to work and comes straight home.

This might not be your situation, but this was mine: Fiance had issues, like your man’s. He admitted the he was addicted to watching porn. He stopped watching porn, and everything went back to normal. Do some research. A porn addict might start only being turned on by porn. It obviously has nothing to do with you and your body because he wasn’t having these issues all along.