Well, for one, even when they start dating Dib still isn't /entirely/ sure that this whole "dating Zim" thing is true because it could easily just be another ride so even when they're out and about, he's still a bit fidgety and it's even worse when they're in Zim's base as he keeps thinking "oh god this is it, he lured me into a false sense of security and now he's gonna kill me and take other the earth." While Zim is just, past that whole thing (1/2)
OH GOSH YOU'RE RIGHT...... it would hurt zim to think "he still thinks thats what this is?" but of course dib does because he's been so paranoid about zim for so long. dib probably wouldn't know any better since he's never felt real security in a relationship and is probably all like "this is a trick"
