First, it's not your job to make sure he can cum. He needs to be able to relax and live in the moment like he does when he watches porn. Other than helping him learn some mindfulness and emotional maturity, there's not a lot you can do about it, and it will likely come (pardon the pun) as her gets more experience and is more comfortable with sex.
Second, I think it's awesome that you can at least logically recognize that you have body dysmorphia and that the way you see yourself is likely far more negative than reality. I know first hand how difficult and painful it is to see yourself as unattractive, and I was 40 before I figured out how to take a more objective view of my attractiveness. I'm glad to hear that you can at least recognize that you are beautiful to everyone else, even when you're having a hard time seeing it yourself.
And finally, there is nothing wrong with you or your vagina. It's really important to talk to your bf about how you're feeling, and to let him know when it's sore or feels bad to have sex. If you tell him, then you both have a chance to work together to find a way to make sex better for you. If you don't, then it will be much harder to do.
If you would like some reassurance and some stories about other women who had similar problems and the changes they made to be able to become better lovers and have mind-blowing, loving, and pain free sex, these books may help:
It's really awesome that you're dealing with this in a healthy way now rather than waiting till you're older when it can be much harder to change. Good luck, and all the best.