Husband went soft 😔

With my husbands crazy work schedule and me being 17w and caring for my 2 year old all day we both are exhausted. It's been a week since we had sex. We usually get it in 3 times a week. He's expressed to my how horny he's been so this morning we tried to sneak a quickie in but he went soft. I instantly became insecure. Hes only 27 and we've never had this problem before so I know it's not age,which he tried blaming. I'm gaining weight and I wasn't prepared with a fresh shave, I don't have a bush just prickly lol but I'm thinking it's my fault😔 has anyone else experienced this and could give me advice? I'm feeling really low about my self right now.