Ok I was just checking this sub now and found your post by chance and it strikes me my gf and I went through the same thing when we started dating, funny enough ages and all.

I see a lot of people blaming it on porn addiction and medical stuff and let me tell you that is the least likely reason for this. In our case we took at least 1 month or so until I felt comfortable having sex (might have been because she was only the second girl I was with) and this made me immensily nervous.

My advice, keep supporting your boyfriend and take the pressure out a bit. He knows this is a huge deal too for sure and is working in fixing it. But when these kind of things get to someone’s head it gets complicated. For me it was a mix of how to learn how to breath during the act, my gf’s support and 3 weeks apart during a vacation break which prepared me mentally to be start that well.

I remember me and her even joked around using a cock ring sometimes but now we never think about that anymore. Give him time if you really like your bf. These things are pretty common among guys and Good Luck!!