lol give him a break. I think he's right to afraid of cockroach, omg I really don't want to remember first time I saw cockroach in streets of Vietnam. I asked "is it mouse?" But it wasn't, it was cockroach unfortunately and really big one. Good that in my country we don't have cockroaches for years, or at least I didn't see them.
And about cooking. I think you should practise your cooking skills more. I know most of Vietnamese dishes have pork inside, but you can try international dishes. Maybe problem was meat and you're talented cook except meat. Isn't it possible? You can try international dishes though, try to make salad, try to cook beefsteak, try to cook onion soup for example. Unfortunately Vietnam doesn't have soup culture much, or maybe they have but I didn't see much. Try recipes online that you can find materials in there. But the most important thing is trying to cook or prepare Korean food. You can try making kimchi or simple things. Please forgive me I don't have much information about Korean cuisine. But you should try simple ones, and try difficult ones later.
One last thing. There is an idiom here. Road that goes to a guy's heart passes from his stomach. So you should make his stomach full to gain his love as well. But I can see he loves you so much. Because mostly guys don't want to be serious with a girlfriend who can't cook.
I'm sorry for long reply, but you should give it a try.