I see two possible reasons for his outburst.
He's cheating. If he's been seeing someone else, and they're doing things together that he finds new and exciting, then he feels guilty and is lashing out at you to try to convince himself it's your fault. This is fairly common when a partner cheats. They need to create some justification for their infidelity that makes you the 'bad guy.' So they stew over it and build this false or extremely exaggerated sense of resentment, until it builds enough to boil over.
His physiological issues in the sack are overwhelming him. He feels as unsatisfied as you do, and knows he isn't satisfying you. This is making him extremely insecure, to the point that any time he knows you're expecting or hoping for sex, he panics and goes on the defensive. Whether he's doing this consciously or not, it's misdirection. He's distracting you from his performance anxiety and ED issues, by going on the attack so that you are focused on your own insecurities and pain, instead of his failure to fulfill your needs.
If this is the case (and keep in mind that I haven't read the comments, so I don't know if you've addressed this, elsewhere), it seems it's past time for the two of you to address the problem head on. If he's incapable of having a conversation about it, you should start with a therapist who specializes in both couples counseling and sexual health. If he can discuss it calmly with you, the first stop should probably be his primary care physician. There are several possible physical causes for his problem. Ideally, those will be ruled out before you see a therapist. He should have his testosterone checked, as well as his blood pressure, general cardiac health, and some possible thyroid related or neurological issues should be ruled out. There should also be a review of any medications he takes, and his lifestyle. Some meds can cause ED in younger men, and several lifestyle factors - drinking, illicit drug use, and smoking can also contribute.
This is seldom a problem that young men just have to 'suck it up' and live with indefinitely. Worst case scenario, the Dr can prescribe some pharmacological sexual aid.
Once the Dr is at least in the process of figuring out what's going on, I'd hope that the two of you would still attend counseling, regardless of the medical outcome. You're past the honeymoon stage of the relationship, he's leaving his sexual peak just as you're entering yours, and your communication skills seem to need some work, especially around sex and expectations. Not to mention, he needs to work on accountability and self awareness, at the minimum.
Meanwhile, please know that this isn't your fault, and regardless of what I said, above, you are under NO obligation to do any of this with him, if you don't want to. Your priorities are yourself, your child/ren, and your job, in that order. And then him, but only if you're willing to continue to deal with him after this behavior. Do whatever you need to do in order to be kind to yourself, first.
I'm sorry you're hurting. I'm sorry you're faced with this kind of situation. You do not deserve to be treated this way. Best wishes.