Just read your updated post. I'll be upfront and say that I sympathise with your BF and from my own experience can see where he's coming from.
From what you write you seem positive and excited that you are splitting from your BF.
From his point of view, his PE and sexual inadequacy has cost him his relationship and your love. It sounds like as far as those things go he's developed learned helplessness - a feeling that no matter what someone does they cannot change the situation. It's like a loss of hope and while it's tempting for people on the outside to brand him 'selfish' to not try to sort things out, this infers that he has a sense of agency and control which it's unlikely for him to feel himself. To him it's like someone demanding of him to grow taller, regrow his baldspot, or enlarge his penis.
These are early days in your breakup and just because things feel less tense and more comfortable doesn't mean he's okay. If he does feel helpless, just because he appears calm doesn't mean he's happy with the situation. You may feel relief and even a sense of release but he may be feeling resignation. If he's the sort of guy that keeps his feelings to himself he may be already distancing himself from you and not showing you his true feelings.
I guess what I'm trying to say is that each of you may be viewing this differently. You're looking forward to a future of relationships whilst he's looking at a future damned by his inability to sustain a relationship through persisting factors perceived to be beyond his control. It may be the right thing for both of you to split up but please be sensitive to how he's feeling, which I'm sure you are. Good luck.