It’s clear that cooking is an area where, for whatever reason, criticism is painful for him. Plenty of people can relate. (What’s that you’re trying to say about my goulash?) What I’m surprised at is how often other people are apparently commenting negatively on his cooking. Who’s coming over for dinner, the judges from “Iron Chef”?
But the next time he’s over the top with his annoyance, pick a private time later on to talk to him about it. “You know how much I love your cooking, and Sarah does, too. But you seemed to get really upset when she made the paprika comment. How can I help you feel OK when things like this happen? It’s something I’ve been noticing lately.” Don’t pile it on, and if he’s not responsive, let it lie. At least you’ve planted the seed, and then you can keep returning to it.
He wants to continue to “spend more time” and “let things naturally happen.” Sounds like a healthy manifesto for dating – until you throw in the part that you’ve been sleeping with him for years and now want something more. That makes the prognosis much more dire.
He’s not giving you much to work with here, and he didn’t seem capable of – or interested in – actually being in a relationship even when he was pretending to be in one with someone else. I think the calculus on “wasting your time” is pretty clear. It’s time to cut your losses and learn a bit more about what you’re really looking for.