Boyfriend can’t cum

When my boyfriend and I first got together, both of us reaching an orgasm was never an issue. Hell I’ve had 20+ in one night. But recently when we’re having sex he’ll get soft and won’t be able to get hard again. In turn he can’t cum. He’s obviously in pain after, even as I’m sitting here writing this he’s curled up into a ball because this is the third night in a row he hasn’t been able to cum. I feel helpless; he says he feels like he’s failing me and just wants to give up. He’s getting more and more frustrated about it and I honestly don’t know what to do.

Hopefully someone has some advice.