My DH used a similar tactic when i was at my "end" on the last leg of a very long ride. He said "if we continue at this pace, we'll get to Portland by midnight" fortunately, even as tired as I was, i was better at math than him and i knew that i'd probably get there no later than 5 (got there a little after 3) so all it did was annoy me.
But i've been right where you were. Sometimes the DH just doesn't get it, and doesn't say the right things, even though they mean well. Did you eat right?
a break with a snack is always nice when you are starting to get that tired and cranky.
You DID ride almost a metric century you know, nothing wrong with that.